You begin where everybody begins, by figuring out what you want to ultimately achieve! :) So here's a step plan:

1. Figure out what you want to achieve with your project. I am talking about stuff like: Do I want it to become a mobile game? PC? Linux? Apple? All of it? Set some boundaries for yourself. Best thing for learning something new is to just pick one of the many options and focus on that. Also remember that there is no best choice as long as you can get it done. Not only what platform, but also personal goals. Is it going to be a hobby project? Do you want to make it a commercial game? Boundaries!
2. Figure out what your options are for your previous choice. Example: You want to make android games. Learn java! You want to make them for the IOS? Learn objective C (I think, could be something else). The importance of the first 2 steps is to narrow down your options.
3. Alright, you have an aim now, a goal and because of the previous boundaries, your choices are now limited or even straight forward to one choice. Time to learn more about the language/tool you want to use. Find some tutorials, make your hello world. experiment.
4. Make your game!

Also, don't get discouraged if you can't get something decent working within a week. learning a new language takes time and changing it within a week will not help. At all.

Good luck! :)