Summarize this article:

You may want to increase or decrease reps and sets based on your experience and fitness level. Remember, a lower rep range for a more inexperienced body builder is 1-5 reps. Medium rep range is 8-12 reps. Higher rep range is 15+ reps. The higher the weight you use, the bigger your muscles will get. However, you will want to increase reps and weights gradually so you don't injure yourself. A good rule for muscle building is to start at a lower rep and increase the weight before increasing reps. Beginners should try using lighter weights with lower reps to get started, then gradually increase.

Summary:
Choose your rep range, set range, and weight.