Sign up for a frequent flyer rewards card through your favorite airline. You will get more benefit out of your miles if you use one airline frequently rather than bargain shopping for the lowest flight each time. Points add up faster when you use just one airline for your travel needs.
Log onto the airline's website and navigate to their frequent flyer section. Once there, decide which award will give you the most benefit based on your needs.
Click the link to the benefit you want. The most limited items are the free flights, airlines always book paying passengers first. Use your free flights for when you are visiting family and if possible, during non-peak travel seasons. Otherwise, if flying is your thing, upgrade to first class for free using your miles.
Follow the remainder of the instructions (from the link you clicked) to claim your award. Some of the awards may have a cost associated with them, especially if you are flying out in less than three weeks. Plan ahead to get the most benefit.