My recommendations - general not only for OP
Can you commit yourself?
What age group do you want to work with? This is important, because the younger the children you are minding, the more 'intrusive' the checks. Bear in mind that, for example, if you are planning to look after the 0-5 year old age group, it is a legal requirement for you to register on the Early Years Register. In order for you to do this, your GP is required to complete a Health Declaration Form about your health, covering your whole life. So bouts of postnatal depression, eating disorders, TOP, diabetes and other health conditions can/will be declared. It can costs £80 - there is no "national charge" - it's up to the individual GP to decide how much he will charge you for filling in this OFSTED form. Some people can find this somewhat intrusive but bear in mind, this is to establish that you are physically and mentally fit to care for numerous young children.
What sort of service can you offer? There are many variations in childminding and you need to decide in advance how you want to work.
Do you want to work on your own or with someone else?
Check out the NCMA website.
Purchase a copy of the NCMA guide to children's safety to carry out a risk assessment on the property you wish to mind from.
Contact your Environmental Health department - you need to be registered with them unless you don't serve food at all.
Although PPG4 can give some protection against planners and hostile neighbours, it is better to have them on side! I know of one childminder's retrospective planning permission being refused. The neighbours complained of the noise and traffic and the planners complained of the congestion. Despite having the Early Years staff of the council supporting the childminder, along with many other supporters, the planning permission was refused, and the last I heard was that the childminder had to close down.
Contact your local fire department. Although there is no longer a legal requirement for fire certificates, they will send you lots of information and it is useful to show the OFTSED inspector that you have carried out all the recommendations.
Book the paediatric first aid course ASAP. I had to wait 2 months to go on a course, and even then, I had to attend at a neighbouring County. Without a valid paediatric first aid certificate, OFSTED will not accept your application for registration.
That's just for starters! If you are still interesting, I can continue if you wish?