Take a pain reliever at least a half hour before your flight to relieve some of the ear pain. Kid's Health recommends ibuprofen or acetaminophen. You should pack a dose of the medicine in your carry-on luggage on the flight as well in case you need another dose before the trip is over.
Spray decongestant spray in your nose to relieve some of the congestion. You should apply at least half an hour before the flight is due to take off to allow the medicine to have time to start working.
Bring chewing gum with you. Chew a piece during take-off to help keep the ears as open as possible during the atmospheric pressure changes. Continue chewing at times during the flight to help keep the pressure even in the ear passageways. Chew a piece especially when the plane is getting ready to land.
Drink fluids, such as water or other beverages (not caffeinated and not alcoholic) throughout the flight. The act of swallowing is similar to chewing gum or yawning--it helps keep the passageways clearer and the pressure equalized. Also fluids are important any time you experience congestion.