...make sure your CV is neat, tidy and well set out. Check the spelling and the grammar. Either write it or print it on the best paper you can manage, and make sure that all the pages are in order and the same size. If you make a mistake, start again, don't just cross out a paragraph and add another on at the end with an arrow to show where it should have been. Don't make jokes in your covering letter. Get the name of the place you're applying to and the person you're addressing right. Oh, and don't leave huge gaps in your employment history with no explanation.
Can you tell I've been short listing this morning? For a teaching post!