I don't know if I can say this sensibly but I'll try.
For my first run through I would make my last set of 1 aprox 15-20lbs less than your known 1rm. Now--depending on the exercise I would go in reverse order and subtract let's say 10-15-20lbs to the set of two. Continue this progression back to 5 reps.
In following weeks/workouts increase the weight for all sets 5lbs or so. In four weeks you are pushing past your previous 1rm.
This may be a bench progression for someone lifting 275-300 max. If your talking squats and rep max of 500, your jumps may be 30-50lbs per set.
You aren't trying to 'max out' on each set. It is quite normal and adviseable in fact, that some sets would be 'easier' than others.