That's what the clutch, that sliding ring of numbers on a drill/driver, is for. It stops the bit from turning when the motor feels a certain amount of torque, or twisting resistance—less at lower numbers, more at higher numbers. As a rule, set it low for small screws and high for large ones. But use a low setting when putting up drywall, so you don't sink the screw's head too far and break the paper. When dealing with hardwoods, a higher setting may help get the screws in, but first drilling a pilot hole is even better.