Vary the training focus:
Endurance
Strength
Growth
Leaning
Repeat it again
Vary the training style!
slow/fast/low rest/longer rest/explosive/pre exhaust
Forget the stacks. They are mostly a waste of your money.
45 minutes max per lifting session not counting warm up and cool down.
Do a little cardio..not much unless you need it to keep the fat down...use the cardio to optimize cardio function! Do it after you lift. Short moderate cardio sessions.
Do some functional work in the endurance phase..then move to the basic strength movements...then on to hypertrophy specific ...then lean up for a bit and repeat.
For Gaining Mass
http://www.discussbodybuilding.com/For_Gaining_Mass/m_111173/tm.htm The top priority is
food, then a multivitamin and an antioxidant.
Consider fish oil or other EFAs.
For the extras..
Creatine (just pure powdered mono, not some koolaid mix) can help with recovery time and up the intensity, glutamine (again, pure powder) can help keep you from overtraining, BCAAs (pure poweder) before and after can halp to spare muscle.