How do you stop spotting between periods?

It depends on why you are spotting between periods. If you're in your teens hormonal imbalance is the most likely culprit, in fact at any age hormonal imbalance is the likely problem - you should talk to your doctor about investigating the cause and look into treatment options. Sometimes spotting can be a result of an STI so if you are sexually active make sure you're up to date with screenings.