There are no 'official' cheats for Draw Something, but there are several ways to make your guessing easier.
If you wish to skip a game without pass, simply close the app and run it again, you'll be allowed to choose another drawing, here's how to do it -
1) Exit the game by clickign the Home Button.
2) Double click the Home Button (this is for iPhone, for Android users, use task manager to close the application)
3) When you see Draw Something icon, touch it for 5 seconds, it will start to jiggle, you can then close the app but touching the cross.
4) Restart the game by selecting the app on your home screen.
Another Draw Something 'cheat' you can try out - this one will make guessing the drawing easier, if you are stuck on a drawing. You take a screenshot of the letters, then exit the game and close the app. When you re-enter the game session, you are given a new set of letters, but the ones that form the words will still be there - you use your previous screenshot to see which letters are still there - and from it narrow down your choices, and make your guess!
'Unlimited Bomb' for Draw Something
Here's a very helpful video, it teaches players how to change the words you're given, without using the bomb. This allows you to save your coins, which cost real money to purchase.
