Try doing 100 pushups the days you work out your chest. I am usually too spent to do chest and back in one day, and I have to wait two days in between back and shoulders. I do arms with shoulders also. I do legs twice a week, one day I'll do some squatting, and the other day I'll work in my deadlifts.
Pyramids are good. But you gotta change it up after a month or so because your body becomes use to the routine. Try reversing your order, but always make squats, bench, shoulder presses, and deadlifts your first exercise.
On my second set I go heavy, just enough to where I can get in between 6-10. I started doing behind the neck shoulder presses first in my routine because my front shoulders seem to be over developed.
Remember, diet is half of getting big. They say use a 4:1 ratio of protien to carbs everyday. Use carbs to fuel your body during the day, and protien for recovering, or mainly after your workouts
