Common problem--how to structure a deal?!

A potential client wants to me to "professionalize the site". From that open ended statement and his futile attempts to clarify I can already tell that this is a potential disaster.

Basically he thinks the site is ugly and I have to beautify it. However, this is a very open ended deal. I am to meet with him soon to discuss details. How do I set up the deal?

He has given no requirements. His only statement is to "professionalize the website". If he pays after the work is complete, there is a potential that he will make me do revisions up the yin yang. I can totally see it now; he tells me to beautify it and i do. He doesn't like it and gives me more abstract suggestions that make no sense to me and I try to accomodate. He still thinks its bad. This goes on for months and I still have no $. He gets fed up and doesn't pay me squat.

Is he to pay in advance? He might not go for that.

Also, I have no idea what to charge for this. There are about 10 actual html files that I will have to basically make from scratch.

Well, for starters, maybe you could design the template, and if he is happy, you could agree on a price to implement the template only and have him pay it upfront before you implement it. The downside of course is if he doesnt like the template and won't want to pay. But I guess this is a common problem you would have dealt with, and you could re-use the template on another site later if he doesnt like it.

Then ask what else he would like done after the template is done,(and offer suggestions). Quote him on these. And so on. Do it incrementally.

Just quote in each single definable change he wants and be as specific as possible, and get him to pay before you put it on his site.