Try opening your mouth as if yawning and see if you can "pop" your ears (hard to explain in words). If you can do it, keep it going on ascents and descents, every few seconds if necessary. Works for me.
I am always careful to be awake for ascents and descents (SLF, not crew!) to do this. If the plane climbs or descends when I'm asleep my ears will be screwed up with the ear on the side I had my head tilted down on usually worst.