Please let us know how we can better serve your needs and what you think about our home on the world wide web.
It is OK as it is, although I can think of one possible improvement: the two clauses which act as the object of the verb know could be switched.
Please let us know what you think about our home on the world wide web and how we can better serve your needs.
This way, you first give a general invitation for browsers' opinions, then you add on a more specific request for information.
A reply would probably be in that order: I think your website is great, I like the ____ and the ______, but could you have more _____ and some ______ ?