Planet 51

First and foremost you must complete all tasks up to and including level 10 of each task. If you do this you should have precisely four more stickers to collect. When this is the case and you have only these few that remain simply replay a task of your choice, and you should unlock your remaining stickers about half way to level 10 of whichever task you chose. Personally I chose the final Car Crusher Task in the Desert to replay since I had just finished it and was conveniently right in front of me at the time. The first two levels I unlocked two new stickers, and the 4-6 level I unlocked the last three stickers I needed. As soon as you press “the A button” to go to the next screen after completing the task it will Auto save and the achievement unlocks. You can see how many stickers you have at any time by pausing the game and selecting REWARDS.