You need to make a log and complete it with youor client present at each meeting. Give the client a copy as you go along. The log needs to contain the original brief and contract between you and the client - simply a letter summarusing what you will do, signed by both you and client and dated - and the date of each meeting, what was agreed, timescale and next meeting date or how client will be informed of update progress if not actually meeting. That way you have a record of what you have agreed to do, and what the client wanted to do. They are very good at forgetting what they told you and swearing blind you were given key info - so keeping a record keeps both sides from getting annoyed. It's also important to clarify if you are being paid to do one amount of work, but the client wants more than this - typically moving from a static html page to interactive pages and online purchasing pages. If you have arecord of what was agreed for the original price then you can demonstrate where the original brief is being exceeded and that it will cost X amount extra - and proceed when client agrees to pay this.