If you are significantly shorter than the tournament average, you can actually play rather freely, since chips won are almost as valuable as chips lost. So you can play fairly normal ranges and look for spots to rejam, and when your stack get even shorter open jam. Its really all about preflop, so learn push fold ranges ideally from working with a program like ICMizer. Or if that is not an option, then study some of the free push-fold chats, which are available online.
The biggest mistake, people make, are being to conservative with a short stack. They fold, fold, fold and end up blinding away, until they have to go with some fairly random hand, unless they get lucky enough to pick up a monster just in time. So my main tip for being the short stack is to get rid of all fear of dying. You are selected to go out as one of the next already, and the best chance to change that is to accumulate more chips.