What can be done to prevent migraine headaches?

Avoid triggers. Migraines are often triggered by various things such as certain foods or smells, allergies, medications, etc. Identifying and avoiding triggers is the best prevention. Alternatively, there are a number of medications available from your primary doctor that can help prevent migraines.
Cut triggers &Trtmnt. Try to kkeep a diary of *everything* you do, eat, go & a diary of headaches (when they start, where they are, how long they last, where you were) hopefully, you'll find a pattern. You can also look into "cryotron" treatment with cold which prevents migraines from coming back in many cases.