What tire and what rim are you running? Some combos weren't meant to be. I use GP4000's with Velocity rims. I use one tire lever and get them off no problem. If I really like, I can get them off with only my hands. Also true for my Mavic rims and the Bontrager rims on my wife's roadie.

Now my MTB running Botrager rims and Panarcer tires was super tough. I switched to Sun Rhyno rims and the same tires are 10 times easier to remove.