If you're prone to headaches, I strongly advise you to evaluate your lifestyle to determine the root cause. There are many types of headaches, each with its own set of triggers.
For general headaches that do not appear to be due to tension or poor posture, I've found that avoiding wheat, grains, sugar, artificial sweeteners and preservatives, and all fluids but water seems to be particularly effective. Those suffering from recurrent migraines would also do well to heed this advice. Just remember to stay the course, as dietary changes do take some time to work.
Migraines are also another common type of headache and it has been my experience that artificial sweeteners, especially aspartame, trigger them in many people. So avoid all diet products.
Two methods that offer more immediate relief include intravenous magnesium and the Emotional Freedom Technique. EFT in particular is usually very effective for relieving pain of all kinds, oftentimes removing your pain in as little as a few minutes.
Home remedies - 6