I'm a scuba diver and the process we use to clear our ears when diving is to hold your nose, tilt your head back slightly and then try to blow out your nose. Don't blow real hard but it should help your ears "pop" and releave the pressure. It's called the Valsalva method below.
Here are a couple other methods from a diving website that might work as well.
Valsalva
How to do it: Everyone knows it; but many people still don't do it quite right. Pinch your nose and gently blow air up through your throat and into the eustachian tubes. The trick is to blow with the right amount of pressure-but not too much, because you can damage the inner ear. You want to blow as hard as you would if you were inflating a large balloon. Blow no longer than two seconds at a stretch.
What it does: Actively opens the eustachian tubes with an increase in air pressure.
Voluntary tubal opening
How to do it: Contract the muscles in your soft palate (the back of the roof of your mouth) and throat while pushing your jaw forward and down. It should feel like yawning with your mouth closed, like you might do when trying to be polite during a boring conversation.
What it does: Tensing and stretching the muscles pull the eustachian tubes open. Some divers get good enough at this technique to hold their tubes open for continuous equalization.
Toynbee
How to do it: Pinch your nose and swallow at the same time.
What it does: Swallowing tenses the muscles in the throat and soft palate to pull the tubes open, while your tongue compresses air against them. This is considered one of the most natural ways to equalize.
Frenzel
How to do it: Hold your nose and forcefully press your tongue against the back of your throat while making a "K" or "ng" sound.
What it does: Contracts the throat muscles to open the tubes while compressing air against them with the tongue.
Lowry
How to do it: Combine Valsalva and Toynbee: Pinch your nose and then blow against your closed nose while swallowing at the same time. It's tricky to do with a regulator in your mouth. But it can help you feel how the muscles you use to clear work.
What it does: Pulls open the tubes while forcing air into them to ensure they get open and stay open.
Edmonds
How to do it: Contract the muscles in your throat and soft palate while jutting your lower jaw forward. For a stronger effect, combine Edmonds with Valsalva.
What it does: Stretches the muscles surrounding the eustachian tubes to help pull the tubes open.