Gospelcom has a reference of useful tips and advice for setting up websites for churches. But especially for making them seeker friendly or appropriate for non-Christians and people from a non-church background.
Their main emphasis appears to be on language. Making the website jargon-free. ‘Church-insiders’ can often forget what it was like before, but for non-churched people the words used can be a huge barrier.
For a carefully thought out website this can be avoided. Of course, there is no subsitute for getting a non-Christian friend to critique the writing. No doubt that they would not hold back with suggestions.
There is also a useful link to resources which are worth checking out.