[jeffmould]

IANAL, but at minimum I was say to form either an LLC or S-Corp. Your costs will be at most a couple hundred dollars, but if something should happen down the road it can greatly reduce the risk of personal loss if a customer comes after you.

Not sure what your business is, or what you are doing for customers, but you may also want to get the lawyer to draw up a simple terms/conditions or contract (depending on your business). This lays the groundwork for preventing problems with customers. If something does happen and your case goes to court it is your word against theirs and without anything in writing their word is most likely going to be a lot more believable to the court system unfortunately.

Other than that, I would keep finances separate. If you form an LLC or incorporate open a business bank account and keep that money separate from your personal money. No cost in doing this and it will make things easier should the tax man come digging into your finances.