-Lift heavy... 4-6 rep range. If you get 6 reps, it's time to increase weight and start all over from 4 reps. Increase 5-10 lbs at a time. Also do incline and decline bench. They are important.
Your body will be going through lots of soreness which is good, this means your muscles are tearing down. This is why you also need plenty of PROTEIN. Protein will aid in the muscle regrowth process. Take amino acids for quicker recovery.
And you must sleep well. The body does it's magic when your out like a light.
I have been doing this same thing I am advising you to do, Its about a year now, I started with like 215lbs , now I'm pushing 305lbs. Check my chest out. Not bad for 40.