For 2D drawing I would say Autocad is how you want to go, or at least a good place to start. If you already have Autocad 2012 on your computer, use it to learn the ropes. At such a time as you are ready for more Architectural applications you will probably want to get Autocad Architecture or Architecture Revit. There are lots of great tutorials on this site, as well as links to many other good autocad sites and resources. Youtube also has lots of instructional videos, if you search there. You can teach yourself quite a bit with the available free resources, and Autocad help materials. If you are sure you want to stay with it, then you should probably get some instruction from an Autocad training facility, an online course, or perhaps a college in your area. Good luck, so much to learn, so much fun to be had learning it. Ellen Finkelstein's Autocad Bibles are excellent reference books, which will assist you from beginner to advanced.