This sounds dumb, but I usually bend way over to that side and bounce my upper body up and down hard to get the water out. I hate water in my ear and this has almost never failed me. Other possible aids:
Tilt and shake your head to drain water from your ears. (What I do.) Gently dry your ears with the corner of a tissue or towel, or use a blow dryer on its lowest setting held several centimetres from the ear.
Put a few drops of rubbing alcohol or alcohol mixed with an equal amount of white vinegar into the ear after swimming or showering. This solution will increase the rate of evaporation of water in the ear canal and has antibacterial properties. Tilt your head and wiggle the outside of the ear so the solution gets to the bottom of the ear canal, then let the liquid drain out.