I did home daycare for alittle over a year. I agree with the other poster the Red Leaf Press offers some wonderful books/information for childcare providers. Buy their yearly calendar and fill out everything. It will have everything you need to keep track of for taxes. At the end of the year, take your calendar to your accountant, and it's all there. This is a must have!
I would advise you to have a clear and specific parent handbook and contract. Many providers request for paid holidays (the parents usually get them at work, so you should too!) and maybe a week or two of paid vacation. Ask around your local area to find out what is the norm. Set policies on pick up/drop off times, what you will do doing the day, illness policy, late pick up/late payment, etc. When you interview a family, so over the handbook with them, IN DETAIL, word for word, and have them initial a copy that they've read and signed it. FOLLOW everything you say you will do. I was often too nice to my parents, and would let the first late pick up or late payment slide, but then it was harder and harder to enforce these things. Do it right the first time, and always follow through. That would be my best piece of advice.
Consider hiring or befriending a neighbor that can help you out sometimes. THings will come up, like dr. appointments, renewing your driver's liscence, you might not be able to afford to close, but you might be able to pay someone to come over for a couple of hours. This really helps your families out, and gives you some piece of mind that you can handle things that might come up during the day - this is occasional, but you will need it. Message me if you want more info. good luck!