There are many ways to begin worldbuilding, and all ways are equally valid. You might have an idea for a history of a world, or you might have a hero or character in mind that you'd like to build a world around, or you might have simply started with a weird dream you'd like to evolve. Everyone begins differently, but this post will be an effort to show a way I like to begin, which I call starting by gestalt.
Gestalt is originally a German word borrowed into English meaning a unified whole. You might think of it as the physical theme of your world (separate from a moral theme or literary theme, which are more abstract).
The question you might ask yourself is: "what separates my world from all other worlds?" Or perhaps "What singular unique feature is a central focus of my world?"
Many great worlds have gestalts, while many other great worlds do not, so if you don't have one, you need not worry about trying to come up with one. Star Trek does not particularly have a gestalt, for instance. Indeed, oftentimes science fiction worlds or realistic worlds do not have nor need a gestalt, as they are an extension of life, which, one might say, does not particularly have a gestalt of its own. Fantasy can also be gestalt-less, as The Odyssey hardly has a unique feature that unifies and defines the story. But coming up with a gestalt can serve as one form of springboard to get your worldbuilding creativity going.
Sometimes the gestalt is simply the ultimate goal of a quest; in Tolkien's Lord of the Rings, the gestalt is the one ring: the magical macguffin around which the entire story revolves. The gestalt of Stephen King's Dark Tower series is the titular tower, to which Roland and company are always in search of.
Othertimes, the gestalt is the very geography of the world. One example (which I am sorry to have forgotten the name of) is that of a world whose inhabitants live on the face of a sundial. Perhaps a particular unique feature of the landscape is ever-present, such as Frank L. Baum's yellow brick road of Oz.
In a similar vein, the gestalt of a world might be the method of travel. The MYST series centers around the idea of transporting between worlds through books. In another comment I discussed how one of my worlds uses waterrises to travel between worlds.
The gestalt of your world can work as a distinct hook to lure readers or players into your world, and want to explore. Having such a symbol of your world makes it inherently memorable and easily recognizable. Few people are likely to confuse the One Ring with a ring from another story, and surely no one has any other name in mind but Oz when they hear of a yellow brick road.
Does your world have a gestalt? If so, can you describe it? Perhaps, are you debating between a number of gestalts? (I find this to be my problem often.) Have you ever started a world by gestalt, only to have it disappear as the world evolved? Are you looking for a gestalt for your world to spice things up? Are you considering one now that you've read this? If you don't have one, and you're stuck on how to expand your world, you might talk about what you currently have, and ask about avenues for adding a gestalt. It's never too late to add one to create the pop you're hoping for, and it can take your world into a brand new and completely unique direction!
This is something I'm less willing to discuss in the open especially with my larger piece. The gestalt is what makes your piece your own, and that is something worth saving (Always a bit paranoid of having work stolen too). I mean in my major piece the magic is probably the closest thing to my gestalt. (The magic is still in the works, but from what I have been working on while I am away it is something I haven't seen). There is also a race in my work that has taken a larger stage in some of my later edits. In my second piece it is definitely the variation in species across legendary creatures. That is honestly the focal point of the whole piece really. I would be willing to help anyone find their gestalt or make the decision to have one or not.
Indeed, I was hesitant for a long time to discuss the gestalts of some of my worlds, too. But ultimately, I found I got a lot more intrigued questions when I exposed it (the waterrises I mentioned in the initial post), and it really got a lot of interest. I gave my thoughts elsewhere about stealing ideas. I think part of it is that a unique gestalt is something that you know is yours and yours alone, and it tends to be the thing you're most proud of. It would be the thing to show off in a movie trailer, or the thing someone describes when recommending a book. So it makes sense on one hand that it's the nearest and dearest thing to your heart, and is the heart of your world, but like the rest of worldbuilding, if the ultimate goal is to share your creation, then sharing the most integral part of it becomes necessary at some point. Some people prefer to wait until their world is complete, or at least until they've completed some aspect of it, like written a novel. I used to, and in some cases I still do (when I hide the entire world itself until I reveal it with a complete product), but I have found that, when you want the audience to come along for the ride of the entire worldbuilding process (as we tend to do with discussion and collaboration such as this), the hook should be the first thing you give an audience, not the last; a lot more conversation and even fandom starts early when you get everything out in the open. I like to think of it as sending your kid off to Kindergarten for the first time. It might be scary for you, and you might be an emotional wreck at first, but once your kid comes back unharmed and full of glee, you'll realize it was the best thing for him.
I'm figuring out a world revolving around an idea that's completely alien to my usual writing persona - an orderly man, strict with verisimilitude. The idea is a young woman on a quest in a world struck by some grand destructive event a few decades ago; the young woman has a plant - something akin to a vine - growing out of her right eye, neither a gift nor a curse, covering her face down until jaw ("the jaw"? I can't tell; articles can be tough). Similarly, I build the world around her in an alien fashion: another character - possibly her follower - bears everything he possesses in a levitating boat behind him; clouds move by the Godwheel; deities live among mortals and act similarly to them while possessing little of their morals and ethics; and so on. Most of my worlds revolve around a single idea or a single character (or group thoseof). Elasi is built to portray the story of Tysie Venn, a homosexual semi-aristocrat who doesn't belong among the high circle, trying to continue his job as a Hero (helper of people, warrior and negotiator, a thousand-years-long tradition among the people he grew up with) after their Corpus was falsely accused of killing the latest emperor, thus ending the Third Rule and splitting the lands, and teaching a young girl his ways while travelling because she has nowhere else to go. This world is tough, and it has rare Wild West-era firearms in a culture of Renessaince stolen from an nation of grey people who have to kill monsters twice their size daily simply to survive; the latter is simply because I thought it would be cool, and there happened to be a reason for it. The New World is about superheroes' human side: how, after they're done thwarting a terrorist plot (of which they could only know through rogue networks or from the government), they'd have to go home and pay the bills, eat, sleep, find love and, simply, live. Superpowers came suddenly to random people around the world in the 90s, and people only had 20 years to come to terms with it - and with the people who wield them now. The action is set mainly in the alternative-history version of the US, the British Columbia. The Dark Side of the World is similar, but instead of superheroes there are mages, instead of the 90s - 1944, and instead of the US - Russia, Europe, Asia and Africa. Here, shamans struggle with their spirits (who most often feed off the dark side of the person - greed, jealousy, crave for attention, anger - and refuse to give further access to magic if they decide to turn good) and general sort of mages can live without electricity, instead opting for magical constructs (computers built out of mana, for example; they drain the creator while they're around and work the better the more energy you put in). And so on. Do you consider those to be collections of gestalts or simply collections of ideas coming together as a single world?
In my attempt to rush out the post, I probably overgeneralized what a Gestalt was. I almost want to take back saying the One Ring of Lord of the Rings is Gestalt, at least in the sense that a ring is a ring, and by itself, is not very unique. We'd be getting closer to Gestalt if we could sum up what the ring does that makes it unique, such as "A ring which grants unlimited power to those powerful enough to wield it" (or something). In your first idea, the Gestalt is most definitely the vine coming from the eye. It was the first visual you described, and it is most certainly vivid and unique. You say someone has a vine growing out of their right eye and everyone can imagine it, and I, for one, can think of no other example of that image. Think of the Gestalt as something visual (though not necessarily a noun), which can be fairly summarized in a sentence or less. The vine in the eye was perfect. What can you say for the other three examples that can have such an instant impact as the vine-eye? As for characters being Gestalts themselves, it's certainly possible. If they're visually unique in some fashion, as to be instantly recognizable, then they certainly can be. The Gestalt of practically any superhero comic is the superhero, since their costumes are outlandish and spectacular. The Gestalt character of the original Star Wars trilogy is probably Darth Vader: his design was meant to be akin to a futuristic Samurai outfit, which is something not seen elsewhere. Do any of your characters from those last worlds have at least one unique feature about them, such that if you drew them, a viewer would be interested to know more about them?
I see what you mean. Perhaps it was me trying to grasp the concept. On the sidenote, I admire your capitalization of "Gestalt", the word being a German noun which, using the rules of the originating language, ought to be capitalized. Does it have to be visual, though? Is Agent Coulson a Gestalt, being the first person in MCU to be ressurected? Pronounce "Tahiti" somewhere around his name in the sentence, and people recognize the character in a moment. How about the Machine from Person of Interest? It's the first friendly and, dare I say, caring AI of such scale in the mainstream media. You can barely draw it - only its interface - but those faintly familiar with the series would probably recognize the... khm, character, as well. How about Chuck Bartowski, for the Intersect? Captain America, for the serum in his veins (shield seems to be in the same category as the ring, even though it's outlandish in the modern era and quite powerful on its own)?
I didn't make up the concept of the Gestalt of a world myself, I read it in a book I no longer own, so my own memory of what it exactly means may be hazy. When I say "visual", what I mean is really "easily imaginable". A Gestalt works a bit like an advertisement: imagine someone has never before heard of your world. If you had a movie poster to show it off, or a tagline, or a one-sentence description, what is the unique and central feature of your world that would make a person say "tell me more"? I cannot speak to those example you just gave, since I don't know of most of them (the obvious exception being Captain America). I would hesitate on calling any of them Gestalts, since, by your descriptions, they do not seem unique enough to capture the interest, without already knowing something about the IP. But if you can describe or show them such that you explain a unique (and important) aspect of them that is intriguing, then they might be Gestalts. Like I said before, to simply say "The One Ring" would have been a bad example, since you'd have to already know what we're talking about to not assume LotR is a love story. To say "There is one ring which grants unlimited power to those who are powerful enough to wield it" can get much closer to a Gestalt, since we are now not only describing an item central to the world, but also describing what makes it unique from other rings in other worlds. Also, I capitalize Gestalt because I get weird about vocab words. I try not to, but I capitalize too much! :p