Catching mice isn't easy. Some use poison to kill mice; however, once a mouse is poisoned it may die inside a wall, leaving behind an overpowering smell. This is why a snap mouse trap is a more effective way of eliminating mice. However, mice are smart and can snatch food from the trap without being caught so you can't just sit a piece of cheese on the trap. You need to entice them to stay on the trap long enough for it to snap shut, which you can do by using chewing gum.
Buy a snap mouse trap from a grocery or hardware store.
Set up the trap before you go to bed. Place it in an area of mouse traffic, preferably against a wall near an entrance hole.
Lightly chew some non-peppermint flavoured gum and use it to secure a piece of food, like a peanut or pistachio, to the trap. Mice apparently hate the smell of peppermint, so choose a fruit flavour so the smell won't deter them from approaching the trap.
Check the trap often.