I have asked questions like this before and have gotten good responses, so I thought I'd try again. I am DIGGING my shoulder workouts lately. My shoulders have started to have really nice caps on them, and I get compliments when I wear something that shows them off (rare in the winter, but I've taken to wearing off-the-shoulder tops

). Anyway, I feel like I've been lifting with 20-pound weights in either hand forever now, and I'm not sure how to increase to the 25s. I can do two sets of 12 (just eking out those last few on the second set) with the 20s, but when I try with the 25s, I can do only a few reps. Should I just stick it out and do as many as I can with the 25s, then drop down to 20 when I can't do anymore? Or, are there any other exercises I can do that will help me get over that 5-pound hump? My new gym doesn't have the fancy-dancy magnets you can attach, so that's out.
Suggestions? You guys rock, as always.