I used to run into equalizing problems in one ear or the other at some point of every diving day. I've gotten pretty good at avoiding and quick fixing equalization problems. I'm sure there are factors particular to every individual but these are a few simple things that are working well for me.
#1 and most important; as I'm swimming on the surface and start to feel a little pressure/stuffiness in the nose or sinuses, to resist the urge to blow air out of my nose into the mask. Instead stop and slide the mask up onto your forehead and blow hard out each nostril separately and then together. Also hock as many loogies as you can muster. If this is done conscientiously I can avoid equalization problems.
#2. Once there is a blockage and I can't equalize I go back up and do #1.
#3. If #1 doesn't work to remove the blockage, inhale a little seawater through the nose and do #1 again. It burns a little but it's worth it.
Other things that I've done in the past are tilting my head sideways and pressing it as hard as I can against the shoulder on the side of the ear that I'm having trouble with. I've also heard about putting the jaw through an wide range of motion. The first three methods I listed however have been working for me flawlessly without having to consider other options.