One of the best things you can do when training is taking time to rest. I have read that some of the bigger gains occur as your muscles are resting.
In my opinion, I would give HIT or Gopros P/RR/S a try. Check them out, there is a wealth of information in this forums, in fact, check out people's journals.
Regardless of this, you need to rest.
Also, do you go to failure or up to a number? Or, do you fail at 5 reps or you count off and go all the way to X amount of reps and stop there? One thing that may help you is forgetting about a number of reps and simply lift until you can't lift no more, thus reach failure.
Gurus, please correct me if I'm wrong, but I believe that rest and reaching failure will help you a whole lot....Just my opinion...