This is easiest to do in World 1-1. First complete the level (Without hitting the Super Mario Block!) Dont jump off the big staircase yet and make sure you have a spare Super Mushroom. Now go back to the beginning and use your Super Mushroom up to level's Super Mushroom. Then get the next Orange Mushroom and complete the level (Without hitting the flag) Now the level should be prett much cleared. Go back to the begining of the level for the last time and jump in 3 fluent motions. The first will be a jump, then a cartwheel, then a flip!