I will do a quick summary of what you need/should do.......
First off.......contact HMRC.....and tell them you wish to become self employed.......and in due course they will issue you with a UTR (unique tax reference)........
the next thing you should do is approach an accountant.....(if you feel you need to, or if you think they could advise you on ways to save money!).....
you will need to SAVE 20% (i Guess) of your income and pay that into a savings account (for your end of year).......and while you are there (in the bank) take a letterhead from your newly formed company and open a business account....(for your customers to pay into!).....
IMO a credit card is the best way to keep accounts simple......but there are variables....to that statement.......pay your credit card off statement to statement and there will be no interest and all company outlay is listed in one place.......simples!......
after this you are on your own.......but you could always ask your accountant you employed earlier in the day! and he will give you the best advice!
all the best
Lee.......oh and good luck........its tough out there!
Lee