I found out this technique which I use religiously whenever I fly (and it works!)...
After take off when you start to feel the pressure buildup in your ears begin, stick your fingers in them and start to wiggle em until cruising altitude has been reached. Its hard to explain the level of wiggling but make sure the fingers are in far enough so that they effectively block out external sounds (so all you hear is yourself breathing - internal sound) and when you move them wiggling the internal sound you hear goes for a split second until you wiggle your fingers back again. If you still feel pressure when you have reached cruising altitude just keep wiggling away for another 5 mins or so until its gone. Remember to repeat the process when you start to descend as well tho!!!
I know that it may sound rather fruity but I can hand on heart say it works (for me at least) and that if it can help anyone else then thats cool. I remember my first flight abroad and had terrible earache for 5 days out of the weeks holiday of which I was nearly deaf in one ear n could not hear! I tried all different techniques to try and overcome this and have to say that the finger wiggling technique is by far the best altho you may get some odd looks from your neighbours