My son has had severe migraines since at least the age of 4 (probably earlier but he couldn't verbalize). We've tried just about every medication on the planet. Right now he is on a daily preventative and Excedrin Migraine (which doesn't eliminate but does reduce the headache).
Some home remedies and lifestyle changes we've tried with some success are: proper hydration (he drinks 3 bottles of water a day), the right amount of sleep (can't have too much or too little), 30 min of exercise a day (something to do with natural seratonin levels), butterbur (get the kind that is PA free to eliminate possibility of liver damage -- we used the brand name Petadolex), caffeine (dialates the blood vessels)