I am actually very anal about time management. If I'm not (ie. right now I should be researching pneumatic systems capable of lifting 150lbs), I stray. I go on reddit, hubski, HN, xkcd archives, blogs, news, Wikipedia, I think you get the point. Thankfully though, I have a lot of practice with discipline of time management. I've been tracking my life in 30 minute blocks in Google calendar for 2 years. It works as well as anything I've ever done.
Basically every month I schedule the next month. I make "all-day" events of projects I need to finish in a time period, and make sure I do enough in the month to keep myself satisfied. At the beginning of every week (Sunday nights), I review what I've done during the week, and convert those "all-day" events into specific 30-minute blocks every day.
The key to keeping up this kind of time management is doing it. As awesome as my planning can be, it will only be as good as my discipline do the shit. And sometimes you don't feel like it. But that is no reason not to. In fact, I find that I typically work better when I started out not wanting to work. This plays a huge role in how effective I can be.
Another thing: be effective. I swear, no specific plans, GANT charts, to-do lists or anything else will rival the time you save by actually doing what you're supposed to. Checking your phone every few minutes fucks you up. Even to check the time. Plan what you need to do, and actually do it. I am in a place now where I have two internal personae. One of them is my planner, who comes out every week to make sure I'm on track. The other is the worker. I basically never question my schedule any more. I just check what I should be doing, and get to doing that. Thinking about when this should be done is a sure-fire way to stop concentrating on the actual work. Be sure you're well organized, and trust that you are.
Oh yeah, and make sure you don't burn yourself out. Taking 10 minute breaks every so often (1-2 hours) is a great way to keep interested and focused.
Specifics wise: I use Google calendar with about 10 different calendars within it. Each has different notification settings and defaults. An idea of the different calendars: Personal, Errands, Personal Projects, Holidays, Work Specific, Work General, Others. (some left out because they are specific to me)
Anyways, the best way to plan is to learn how to follow that plan. For long term stuff, GANT charts and project management software works. For short term, to do lists are a classic. For scheduling, google calendar works well.