Really no tricks.They just get stuck period.Some come right off some Ive actually broke the rotors getting them off.I used my SnapOn air hammer with a hammer tip on most.Just spray and work around the center.Some I even had to heat.then a good coating of antisieze on the hub before install.Just did a set of rear discs on my nephews.One fell off one was rusted on and a bear to get off.Also try prying on one side a bit while hitting the other side.That lets them pop off sometimes.I guess I dont have to tell you to remove the little factory clips that hold the rotors in place.Rocky