I am a contributor to the UK site Freelance Advisor and they've produced an excellent beginner's guide to starting out freelancing (or contracting). It covers a lot of the practical stuff about setting yourself up as self-employed in the UK including book-keeping, tax, invoicing and chasing payments.
It's a brilliant compliment to Screw Work, Let's Play because it covers the nitty gritty stuff and is updated regularly.
Browse the guide below:
Also be sure to download my FREE Play Toolkit with worksheets, guides and several hours of audio instruction to help you discover which work you'll really enjoy and how to get paid for it.