OK frist thing fisrt what game engine will you use? screach the internet everywere i havnt found 1 yet second are you a coder or artist if not coder par up with one if not artist par up with 1 third what will the game be about it good to have your own style game but you might want to think to your self how will i do this thats my tips
Well first, You have to learn a programming language... Like maybe: Python, Java, C++, C#. I recommend Python but thats just my preference. The thing is you just don't make a game in one day of learning. Also you don't want to try to make a 3D game as your first game. What I did and still am doing was first I did a lot of text based games, then I would do 2D games, then i would do 3D games.
You should concentrate on what you enjoy doing if you make a game. If you don't like to program and you are the programmer the game will most likely end. If you are going to post on here you need Flash CS3,4,5,6 haha. If you want to post on the app store you need to use the developers kit on their website. I don't think you can use flash for iPhone games. (if I'm wrong feel free to prove me wrong)
as for genres, make your favorite genre. If your favorite genre is platforming and you try to make a shooter you don't know half as much stuff as you would if you tried to do platforming game.