Pullovers should be part of any chest routine. Use them as one of the last exercises of the workout after other muscles are already fatigued.
Finish your next chest workout with dumbbell pullovers: 3-4 sets of 12-15 reps. Focus on squeezing the pecs to initiate the movement up from the bottom position and work on holding the squeeze throughout the rep.
I'm going to describe a little 6-week program that I call Tsunami Training (I'll get to why I call it that a little later). It's based, for the most part, on training methodologies that I picked up from Ian King and Charles Poliquin, with some razzle-dazzle thrown in by myself.