What can i do to prevent an ear infection?

Depends: Outer ear "swimmer's ear": avoid getting water in the ear canal or make sure you get any water out. For middle ear infections - otitis media: usually caused by dysfunction of the eustachian tube and a viral infection (cold) or flying can predispose use. If you get a cold, use afrin nasal spray (< 3 days), saline nasal spray and avoid flying if you have a cold if you can. If frequent - see your ent.

Ear Infections: If you mean external ear infection, then the best way to avoid one is to keep your ears dry while bathing and swimming. Also don't use q-tips or other devices to clean ear canals. Middle ear infections can't be prevented per se. They can occur during or after a cold, or during flare up of allergies. They can occur for no clear reason. In general, the better your overall health, the lower the risk.

No q-tips: There are inner (middle) ear infections and outer (external) infection. Middle infections occur most often with colds and to prevent these hand washing is the key. For outer infections keeping some wax in the ear is crucial. Q-tips remove the wax as does alcohol and peroxide. Keep these out!