Anyone with Range can beat Garen. Make sure to have Boots so he can't catch up with you, ward the bushs in your lane so he can't supprise you. Make sure to watch him carefully, if he runs in, expect a flash-engage and flash out the second he flashs. As for non-Range. I beat Garen with Irelia, Jarvan. A friend of mine beats him all the time with Renekton.
Just don't sit there and eat his spin, get away from it. Watch what hes doing in the lane, if he blows his spin on creeps, dive on him immediately as the Cooldown is fairly long.