Last week I was at an inspirational Ty Newydd writing course in north Wales, led by Mavis Cheek and Francesca Rhydderch. One of the many, many things we learnt in passing was Kurt Vonnegut's 8 rules of writing. I recommend reading them if you do any creative writing. They're in his usual dry and irreverent style. If you enjoy them then his talk about story structures is well worth watching too (I have seen it many times!)