basically, do a set (like 8 reps) with a high weight, then do another set (another 8) with like 60% of the first weight, then a third with about 60% of the second weight. You can make your second and third sets a bit heavier in relation to your first set is ya want (like 80% maybe??) I usually do three consecutive 8 rep sets when doing drops. I find they work really well for burning out biceps and for deltoid side raises.