ive been song writing for about a year. Multisandia was right, best way to get better at song writing, is to look at others songs and start buy fusing them to create your own, just taking snippets and stuff, then look at the way they were written and style and take it on board in your writing. I play guitar n bass and piano, and i foudn the best way of writing great stuff is just improvising on a good day you can come away with some great riffs!