Actually I find that a compilation of all the answers gets to make the best answer <img src="smileys/smiley1.gif" border="0" align="middle">
- Follow as many tutorials, C2 examples or even items from the how do I FAQ as you can, they'll give you experience on how to make things from a technical point in C2.
- Then try to "build upon" those tutorials, or simply try your own hands at some of your own ideas, making playable and enjoyable prototypes you could distribute and get feedback for.
- Focus on some prototype that is fun and has a small scope and finish it/bring it to the state of completed game (polish, release quality, a start, a middle/progression, an end).
- Let a bit of time go by, analyse what went well on your game, what went wrong and start all over again with bigger/more complex prototypes
- All along be sure to read as much as you can on the subject of game design; this forum is a good place to start, be sure to check most of the topics and never hesitate to read/watch/follow the external links that might be given.
The best advice, I think, for a total beginner (but also the hardest to follow) is to start with a small scope project.
Most beginners want to redo some game they enjoy that was built over a big amount of time (months/years) by a team of tenth/hundredth of professional people.
It is an unlikely goal to achieve as your first project alone.
The smaller the scope, the "simpler" it will be to finish/complete a game an get the reward of being an actual game maker and be able to handle bigger projects afterwards.