You DO NOT set your blade at 1/2 credit card!!!! About 10 times too much. That has been stated and stated not to on here.. I have posted how to set the blade depth correctly on here. You set the blade depth like this. And you should barely see or feel the blade tip out of the blade holder.
To start with, you should set your blade depth correctly, by taking the blade holder out of the machine, and firmly cut across a piece of scrap vinyl, you will be cutting. You should only be cutting the vinyl and barely a mark on wax paper backing, Adjust blade to get there, Then put the blade holder back in machine, and use the force of the machine to get there, same results, only cutting the vinyl and barely a mark in wax paper backing.