Like death said, it really depends on what works for you.
This is how I would go about it:
1) Sit down and think about it
a) What kind of a game you want to make?
b) The look/style of your game?
c) What you can do with blender? (be realistic)
2) Doodle (yes, doodle)
a) Start drawing a variety of objects that you would possibly want
to end up in your game
c) Draw some more
3) Pick the sketches you like the most out of the doodles and redraw
them into a "reference picture" (a picture displaying the front, and
side view of your character or anything else that you would want to
1) Import a reference sketch into blender as a background image
1) Skin & Rig any characters (or anything else) that requires mesh
2) Use IPO curves to fine tune any animations (if any need to be fine
tuned that is).
------Scripting/Logic brick setup---------
1) Use logic bricks & python (if necessary) to add the desired
events/functions to your game.
1) Anything that you find to be "lacking" in any way or form, go back
and fix it, or at least make it better.
2) Run and test the game yourself
3) Make an executable
4) Upload and share with the community.
These are just broad strokes, but if you plan everything right in the beggining, you should have less trouble in the end. I know that’s just plain logic, but there are so many people who don’t pick up on that (I was one of them).
Im glad your taking time to plan things out.