Hi email@example.com, welcome to the forums
This question is much too vague and ambiguous.
Every site is different so you're unlikely to get any useful information unless you supply more detailed specifications.
Seeing as you have a website that's business is creating websites you'll surely understand this and be able to do so.
Note to forum members
Until the OP returns and clarfies the question, Please read "Fluff" posting - what is it and how do we deal with it?