Since others have already covered some of the skill stuff...
Figure out what you need. If you want to make, say, a 2D game about killing zombies, write down all the art assets you need. Zombie idle animation, zombie walking animation, zombie attack animation, zombie death animation, foreground art, background art, object art, etc etc. Same goes for programming and design. This will give you an idea of you're over-scoping. A lot of people, for instance, want to make an RPG - but it's a lot of effort to do so.
It's hard work and it not be fun at times. Things will not work the way you want and you will not be able to do what you want. The sooner you realize that, the easier it will be. Braid was a two-man project that took 3-years working full time to make and the creator spent 200K of his own money to help fund development. If you're trying to make even a smaller game like Braid, you're going too far. Stick with a 1-screen, simple simple simple concept first. You'll learn whether you're just curious about games or you actually like making them.
Mod first. It's pretty difficult to jump straight into full game development without guidance like a school program or a heck of a lot of personal dedication and sacrifice. Modding is easier and can help ease you into things. As an artist, find games that let you import or otherwise create art and try making some things for them. It doesn't matter if you like the game or not - chances are, you're not going to like a lot of the work you do so get over it. MUGEN for instance uses sprites. Elemental has both a in-game editor for basic stuff and probably supports custom stuff. Fallout 3 is easy to mod as far as terrain and using 3d tiles.
You sound like a guy with an idea that can draw. Get over it. You'll need to contribute and will not be able to sit back and be a boss. If you want to do art, make art. If you want to do design, design stuff. In a small team, you'll have to do all that. Right now, probably your best bet is to write up a game design document as part of pre-production. You can find an example or two on the web. If your design document for your game is less than 15 pages or so, you're probably doing something wrong.