As little as possible. I just want to figure out the timing needed and adjust any ingredients/spices if I think the recipe can be improved upon.
That is a tough question. Experience is the best way of course but If I am doing something new I tend to write down my cooking plans and work backwards from when I want everything to come together. (eg. - 4 hours: make broth; -45 minutes: chop onions and garlic; -30: warm broth; -35: start risotto; -2: add truffles; -1: add Parmesan). Then I put the instructions for all the dishes in order so everything comes together on time. That will also let me know when I need someone to help as some tasks have to be done at the same time. I keep these plans to use in the future as well. And right before I start I will change the minus times into exact clock times so I do not have to do math in my head as I cook. (eg. -45 becomes 7:00; I have a bad habit of inviting people over at a reasonable time and then getting caught up in conversation and drinks so I tell people when they come in that I have eg. 55 minutes of work to do so that they can tell me to get off my ass and start cooking at a decent hour.) Recipes are also only used as general guidelines and I like to adjust things like spices or cooking times to my liking so sometimes it says eg. cook for 40 minutes but I would find out that in my oven it is better for 35 or 45 minutes. Or I find that something can be done ahead of time and the taste does not suffer if I let it sit. Sometimes it could also be something as basic as thinking I could get an ingredient easily but it turned out that it was way too expensive or it was impossible or very hard to get so I needed a day or so to adjust my plans or find the ingredient. So if I look for it the day before I have 24 hours to solve any problem that may arise.
Thanks. I'll see if I'm to make use of that soon enough. On the sidenote, it's amazing how varied and off-topic discussions and conversations on Hubski can be. Here we are, talking about how to prepare for a massive cook-off under the flag of me advertising my blog. That's cool as ice. :)