I know you've gotten a lot of good advice and what not but here is my two cents.

Try starting your Shoulder day with a superset to pre-exhaust. I like to do a seated barbell shoulder press (smith machine or military) and superset with flyes. GOOD burn doing that man, then at that point if you keep your rest time down to like a minute (at most) between sets and 2 minutes between excersizes you'll fire them up