>Pinch your nose tightly, close your mouth tightly, and blow until both ears 'pop'.<
Be careful how you perform the "Valsalva manoeuvre" - blow gently . Many years ago I was recovering from a cold and did this procedure and in the process perforated an eardrum. It tooks a few weeks to heal before I returned to flying duties. For a long time afterwards I allowed nature to take its course - if my ears didnt clear on descent I waited until they did!
That said in circa 14,000 hrs flying I have only been totally unable to clear my ears on descent on two occasions and perhaps surprisingly I was not suffering from a head cold. Withing a few hours on the ground my ears cleared "naturally".
Nature makes it more difficult to force air into the middle ear to protect from infection. I think when you do a lot of flying ones eardrums before more elastic!