First, close up any openings they can use to get in. Steel wool works to plug up small holes. Second, get some fox urine from a hunting store and spread it around the outside of the garage. You won't smell it but they will.

Mice get leary of snap traps but they don't seem to catch on to glue traps. Having a mouse stuck to a glue trap seems to attract other mice to the glue trap. Use the large rat size. They drag the mouse size around and can get loose. Check them frequently and replace them quickly. I used the rodent block in the center for bait.