Warm up the muscle by doing a few light sets. I like
12-10-6-3-1 (the last two being weight acclimation sets)
then I go for sets as heavy as 4-6 reps to overload the muscle and force it to adapt. Some muscle groups require larger reps (lower back , at 6-8) or calves (12-15). I think you should start with a light weight if you are just starting - warm up properly, and then try to go heavy. It's really all about experimenting. Track your progress - it helps in the long run.
Peace