If you have built sufficient strength on the compounds, time to move on to hypertrophy phase and periodization.
Start learning to force your muscles to grow with supersets, drop sets, stripper sets and changing the rep schemes every week or so.
Try using CT's HSS 100. I've been using a similiar style of training for years. This shit really works.
I've gotten a ton of mass by learning to stay in the 6-12 rep range for most body parts for a full minute. How this is accomplished is through supersets and drops and strippers... each part in this same rep range usually. Try to read up on TUT(time under tension)... this will be the biggest factor in you gaining size and putting on mass.
Stick with the basics, go heavy with good form and eat well... easy as pie righ? That's all you really need to know other than learn to push your muscles through the pain barrier if you really want to force them to grow. This is best accomplished by some type of forced reps and continous tension, roughly around 40-60 seconds... and that doesn't mean a light weight for 40-60 seconds. It means probably 3-4 different exercises with no rest in that time frame of 6-12 reps per exercise. Try it out, this info I have provided is not a secret, but it is hardly ever used and this is the concept behind breaking a muscle down and rebuilding it. Use certain periodization techniques to trigger hypertrophy. You can do a routine for 2-3 weeks and gain nothing, but its the switch of the alternate periodization routine that triggers this response to change.