When I have an idea, it usually comes out of a song I wrote (check sig for examples), and I start building a world off of that.
I usually start with either a sketch, or some pixelated chunky MS-Paint graphics.
Since my graphical capabilities are limited, I am stuck using the fonts SmallFonts and Atari Classic fonts so any project I make doesn't look amateur- to me, aesthetic and style is very important when making a game, because having photoshop shit with lazy gradients and scribbled graphics is NOT something I want to play.
http://i417.photobucket.com/albums/pp25 ... eview4.jpg
In here i just kinda started out with a simple "Explore a cave" type game idea, game up with a simple MS-Paint visual aesthetic, and went from there. Since i've hit a roadblock with death animation, I have stopped on this project for right now, but all in all it is a good example of starting from a simple concept, and then working to your strengths and being effective with what you have.
Are you not a good artist? Make your graphics simpler (if you can't hire someone else)! Not good at level design? Take cues from your favorite games and see how they get you through them. Are you a music type of guy/girl? Play that strength up, while focusing on a single design route and sticking with it, I'd say. I mean, it's no use having a super-detailed player sprite with a complex and emotive score if all he is going to do is jump around some purple rectangles. When I try to make a game I try to have everything on the same page, so at the least, it's consistent. Right now, that means blocky, Atari-esque graphics, but I'm fine with that.
http://i417.photobucket.com/albums/pp25 ... eview2.jpg
Here i started out with a simple idea: Make a shmup. However, I didn't (and do not) know how to go about doing that, so the project became not possible with my level of skill. So I scaled back, and said "Well, if I can shoot things, how about I just try to avoid them?" So a weird space-ship frogger-esque thing was born, and nearly done. But you can see I kept the same aesthetic and played to my strengths (the enemies are all consistently animated, the music is appropriate, and things are kept simple).
All in all, I think this is important to consider when you want to make a game (and take this as you will, since I've never finished one... yet. I'm close ;o )- - -
1) If you have an idea, see how much your skills can make that idea a reality.
2) if your skills are not able to bring about what you want to do, you do one of three things:
a) learn more programming
b) seek outside help to bring your creation to life
c) scale back your project into a manageable affair
All three are legitimate ways of going about things, but I tend to try and keep my projects as simple as possible so I can actually be able to make them (though I've made enough topics in the help section to show that option b is often necessary, too!).
3) aesthetic is the most valuable assets an indie-laptop game can have. If you have a great game idea, but it's buried under a garbled mess, no one will want to play it. Aesthetic is a way of making your game recognizable, as well as allowing people to enjoy the game as a seamless whole. I've noticed that all "great" games have a singular aesthetic, and we hardly realize it because we're having too much fun playing them.
Just my thoughts.