Before you touch the flag at the end of a level, make sure your coin total is a multiple of 11. ( 00, 11, 22, 33, 44, 55, 66, 77, 88 or 99). Touch the flag when the last digit of your remaining time is the same digit as your coin total and you'll receive a 1-Up.(For example, 55 coins and 275 time left, or 11 coins and 081 time left)