My advice to you is dream big, but start small. You don't have to make copy cat games to learn how to make a game, it's a good idea, but why waste time on that when you can be working on your own game? First thing I suggest is to really finish up the basic idea of your game. Don't spend time thinking about updates, patches, mods, and hiring 100 graphic artists. That stuff will happen when the time is right, or not at all. What most of us beginning game makers don't realize is that we can't chase the big dreams at the start. Chase the little dreams first. Think of your game as a baby, and you need to watch it grow, how ever slow or fast it needs too. Don't waste lots of time on a game that may not even be a hit. Get a small working version of the game together, then release it into the wild to see if anyone even likes it. Graphics do not matter in a new game, did you hear that part? graphics do not matter at all. Don't worry about that in the beginning. Just put something together to get a feel for the game play itself, since that is what makes a game good or bad. The graphics can always be improved later.
Depending on what type of game you are making that will determine your development environment. For 2D games you can use XNA game studio or gamemaker, If you want to go 3D I would suggest Unity3D for a beginner because you can setup most of the level without too much coding. A cool thing you can do with Unity3D is make a 3D game look like a 2D game. They have just released a new update with new tools for making 2D games. There are lots of tutorials to do different things on YouTube that will help you out. Another great thing about Unity3D is that you can code the game once and release it for most platforms, like Xbox, Android, IOS, etc. This will save you lots of time. Graphic artist can easily import 3D models into Unity too.
well that's my advice for you , hope it helps you out.