Ace Current Level
To ace any minigame, simply select it from the Story Mode menu, then wait for the entrance to disappear. Now pause the game, then hold down the PlayStation button on the middle of the PS3 controller. A pop-up menu will open. From here, select "Turn Off Controller." The game screen then will read "Press PS button to play!" Press the button as instructed, then unpause the game. You will appear at the level's scoreboard with zero lives lost, therefore acing the level.
Skip Tutorials
While they aren't proper levels, the tutorials in "LittleBigPlanet" teach you the basics of creating your own level by giving you challenges to solve. There is no way to ace a tutorial, but it's necessary to complete them to gain new materials and stickers for your own use. In that sense, the more rudimentary tutorials can take up time. To gain the ability to skip any tutorial, press the following buttons in order during the credits screen: down, up, L1, L2, R2, R1, triangle, X.
Using Checkpoints
If skipping to scoreboard seems too easy and you want to ace a level yourself, it's going to take a process of trial and error. Luckily, Sackboy is provided several checkpoints from which you can retry certain challenges. The checkpoints are small doors that will light up when you pass them, with a ring that tells you how many lives you have left. If you die in a level, negating your "ace" status, don't restart right away -- restart at the checkpoint and keep trying until you know for certain how to pass a section. Once you've mastered it, restart the level and try again without dying.
Easy Multiplayer Prizes
In addition to the achievement of acing a level, there also are multiplayer prize areas in the majority of levels that require two players to unlock and contribute to its 100 percent complete status. However, you don't necessarily need a friend playing along with you to get the hidden items here. Most multiplayer areas can be beaten by using two controllers at the same time. Just complete the level by yourself, and once you reach the multiplayer zone, press the PlayStation button on the second controller. Then, turn off that controller and finish the level yourself.