I learnt Autocad Years ago. I used it for about 6 years
A course at a college is a good idea, and also get a good book.
Once you get used to the commands and techniques you just need to practice and this greatly improves speed, just takes a little time. Autocad itself has some inbuilt examples of dwg's in it, though i'm not sure whether they are still in the latest version. If you haven't got these I may be able to dig them out for you (Not promising as may not have them myself now). I don't know of any sites, but haven't really been in volved for a while so I guess things could have moved on a bit.
Only people I know who use it are other pros and part times contractors.