I've had eustachian tube problems since November 2003. In that time I've seen a number of specialists and GPs, each one giving a different diagnosis and advice (none of which has helped). What I've learned has been to be more aware of what my body is telling me.
For example, the Eustachian Tube Dysfunction seems to be worse when I am fatigued or stressed, and this is true whether I'm flying or on days off.
I'd advise anyone having difficulty equalizing pressure in their ears to be more aware of all the other circumstances (eg associated pain/discomfort like jaw or sinus pain, when it happens, what kind of day you've had, etc), and note it all down so that when you go to a doctor you can give him the full story.