hi od, well, im kinda in a similar position in some respects to yourself. im getting into openGL with vc++6. if you want to speed things up for yourself go grab SDL www.libsdl.org
it will help with taking care of lots of stuff so you can focus on your game easier.
if youre confident, start by working out the data structures and stuff that youre going to use to handle the game data (maps, models, world settings). then once you have that going, go and create some editing tools that output files for those data structures. this way you can create objects and testing environments relatively fast. you'll need to implement the player interface and physics at this stage, and then start testing how things will move. if you get this far, then you probably will get your own ideas of what comes next.
the other way, the way im trying, is to do everything small, then work my way up. ive created a very rudimentary terrain that uses height maps, so my editor is MSpaint. im working on the very basics of the player interface (mouselook, movement, no physics yet) which just uses global variables rather than classes. and my next step will be adding code to import milkshape models. and then maybe adding matrix math to handle movement(rather than what i have now).
anyways, there are plenty of people here that know way more than me, but i think the best advice, is dont try and do everything perfect at once, take steps, it should be easier that way, good luck :)