In the first few levels there is some hints and you will want to pay special attention to the one that says you can push other dice. That is the key to solving quite a few of the levels.
You have as many tries as you want on a level, but I think it is more fun to plan your moves in your head instead of using the trial and error method. I'll have to admit, however, to doing a little trial and error myself when I got tired of taxing my brain.