* If you jump off the edge of the screen, you will appear on the 
  other side. This can quite often be of help, should you get stuck.
* The game has some glitches that you can use to your advantage. For
  instance, if you jump off the edge of the screen to the other side
  and try to catch hold of blocks that are partly off the screen, you
  will appear on top of these blocks. You can also get through some 
  tight spots in this way.
* I find that it's generally safer to jump on the side of a falling 
  block, not directly on top of it. This way, there's less chance of
  being crushed unexpectedly.
* The most important thing, I think, is to keep moving. Always. If 
  there's nothing to jump onto, keep jumping up and down to see what's
  coming your way.