One thing that gets mention quite frequently, but is hard to stress the importance of, is reading the Terms of Service (ToS) and Acceptable Use Policy (AUP) BEFORE signing up.
Notable things to look for:
Are services contract based or month-to-month
What are the network / server uptime guarantees
What is the guaranteed level of support
What is the cancellation policy
What is the refund policy
What will cause your account to be removed without notice
(if you are worried about this, stop doing naughty things)
How is your data guaranteed
(any lawyer written document will have one of these, company's like to protect their own rear-ends)
These are just some of the main points which should be outlined in a ToS/AUP.
Why should these documents be read in full before agreeing to them?
As a paying customer you should want to know exactly the situation you are entering. If data is not guaranteed you should look for off-site backup options. If the money-back guarantee only lasts for a week, you know this up front. You won't inadvertantly violate any part of the agreement and potentially lose your valuable data. If you have customers, your own ToS/AUP will be accurate as it will need to reflect your providers'. Too many times we have seen angry ex-customers come into a forum complaining about lose of server, data, time, money, etc..., because they did not bother to read the service agreements. Smart companies have these documents written by experienced lawyers, and the agreements are air-tight. This may come after being burned by a customer, or from prior business knowledge, but you as the customer are responsable for understand the documents. The company is in no way liable if you don't read them, which is a situation you definitely do not want to be in.
This is by no means a complete list of the important sections or features of these documents, just a truncated list to help stress the importance of taking ten minutes to read them. If after you have read them you still have some questions, ask the staff. It is much better to delay ordering by an hour or a day and to know what you are getting into than to rush into a contract and waste your time and money.
I hope this helps some of you, happy hosting.