GTD is a complex system meant to simplify and be simplified based on needs.  Plenty of people have customized it for geeks and busy people.  Gina Trapani and Merlin Mann are, perhaps, two of the most well-known.  I use many of their tips and suggestions, but I've had to customize it for myself even further (and I wouldn't have it any other way).  There are some techniques I've tried that work well, and some that don't.  Here are a few of my suggestions and approaches.

    First, make your todo list and similar files easily accessible.  I use Dropbox for this, but there are plenty of options.  Many colleges (like mine) offer server storage to students or you can even run your own, but I like Dropbox because of its wide integration with the services I use.  This way I can access it through Notational Velocity or the terminal on my desktop and SimpleNote or Dropbox on the go.  It doesn't matter how you do it, but make your todo list always available (and up to date) so you can leverage your spare time and keep on track.
    Second, make your todo list simple.  Tags, contexts, calendars, lists, types, the list goes on.  These features are only useful if they make it easier to get things done.  For my part, I use one todo list (my inbox, if you will) where I file items with a context, priority, and project if relevant.  My approach was inspired mostly by Gina Trapani's wonderful simplified GTD and doable todo list (which were in turn inspired by several other GTDers – hit up the bottom of the post for links).  My other big influence was, which uses a limited syntax and keeps things simple.  As a college student, many of the contexts will be fairly limited in scope (almost all of mine say @computer), so find a system that gives you the information you need quickly without bogging you down in menus and options that you'll never use.
    Third, don't list general homework assignments are repeating, empty tasks.  I did this for a while when using 2Do/iCal, which easily support recurring todos.  Listing "Reading" every Tuesday and Thursday every week was not helpful.  Instead, enter "Read Foucalt's History of Sexuality Vol. 1" for next Tuesday, "Read Dickens' David Copperfield" for next Thursday, and so on.  Being specific about which assignment needs to be done when helps me avoid feeling overwhelmed and being blocked by procrastination.  It's a little surprising, but not having to look farther than my todo list for each assignment makes it remarkably easier for me to get my homework done on time.
    That's pretty much it, in fact.  Like a good todo list I've tried to keep this from being a braindump of everything I do to process and use my list.  These are the most basic rules I use to keep myself organized, and they are how I arrived at the decision to use todo.txt and  As I noted above, each person must customize his or her todo list and process for maximum effectiveness, so don't take anything I've said here as gospel.  Go out, change it, and get stuff done.