I don't know much about websites/domains but I would have thought the best way would be to wait until the site is finished before you upload it the web.
If you have a page that says this domain does not exist (or similar) then you will be turning people away. When it does become ready no one will want to look.
Alternatively, you could put a password on it so that only people you nominate would have access to it.
You may also get a better response if this was posted in the Web Design Forum. Lots of experts there.