Is there any way to help prevent the return of my cancer?

Possibly. Cancer prevention is variable from cancer to cancer. This would depend upon what type of cancer you had and what was done to treat it.
Need more info. Depends on the kind of cancer, need more info. Stopping smoking is very beneficial not only in decreasing cancer risk but also in decreasing risk of heart disease and many more.
Cancer prevention. It depends on the type of cancer you had, but good nutririon and excercise, and continuing the follow-up care prescribed to you are the best preventive measures you can do now.