Well my main thing is to hit 16-25 reps in a given excercise with the same weight. 95% of the time I use weights that should allow me to do it in three sets, once the total reps for all three sets equals 25 or more I add more weight, for example tonight my BB shoulder press went like this set 1: 10, set 2: 8, set 3: 7. All of them combined equals 25 so next workout I will add 2.5%-5% more weight to it, which will drop me down to around set 1: 7 , set2: 5, set3: 4, and build back up again from there. Sometimes though I get a little overzealous with the weight selection usually when it's a new movement in my rotation and I go too heavy, I will add a fourth set so that I can complete at least 16 total reps, it looks pretty much like this set1 5reps, set2 4 reps, set3 4 reps, set4 3 reps, by next workout though I better be able to get at least 16 total in 3 sets. Generally I can add 3-5 total reps each workout, my cycles last 6 weeks after which I evaluate which movements are stagnating and need to be switched out and which ones should stay.