Best way to prevent ears blocking during descent?

I always take gum with me and as we are taking off and landing in a plane I chew it and it seems to take the pressure off my ears.

A few things that help:  Try to keep them from plugging on descent by holding your nose shut, and then "try" to blow your nose; chewing gum or sucking on a life-saver or other hard candy.  I've also heard that for babies, moms have carried washcloths, upon the decent they've asked for a cup of very, very hot water.  Soak the washcloth, then hold over the ears.  The moisture should help keep them from clogging up.

Try fake yawning. Stretch wide and it might help.

I either chew on something or drink water, seems to help.

Suck on a sweet!

Styrofoam cups over each ear, it works great with babies, you may look funny doing it as an adult but then who cares

Try a scuba diver ear equalization (and don't forget to wiggle your head) see: https://www.diversalertnetwork.org/medical/articles/download/DiversGuidetoEars.pdf

eating a hard candy helps pop the ear

I take sudafed before taking off and this works well for me. If I forget, mine are clogged until the next day!

A product called Earplanes works for me most of the time. I put them in well before landing (you can wear the whole flight if you wish). I buy at Walmart. When I say 'most' of the time I am saying '90%' because there is always some stray landing that nothing helps!

Try all the other suggestions but if all else fails take sudafed.  This is the only thing that works for me to stop the ear pain and weird blocked ear feeling of taking a flight.  This was my doctor's suggestion.

Chewing gum works for me every time.

I have to do a "Louis Armstrong" :D 
That is, I close my mouth tight, pinch my nose closed, and try to force as much air into my mouth as possible, so my cheeks go out like Louis's.  This helps equalise the pressure through the Eustachian tubes on descent. 

But avoid doing this if you have a bad cold: it can lead to ear infection.

I try to pre-empt all this by keeping everything clear by sniffing camphor (anything like Vicks brand), and chewing mint gum, yawning, wiggling jawbone around.  It really is a suite of approaches, but when I discovered the Louis Armstrong manoeuvre, my life was suddenly devoid of airplane pressure descent pain!  Good luck :-)

Noise canceling headphones seem to work for me.