September 20, 2008 2:13 PM EDT
I would recommend reading lots of patents similar to your invention. (There`s a patent search on Google that works great for this.) Use similar language and detail in writing your provisional application. Add every feature and variation you can think of. More is better! And no need to include claims at this point, but first do a search to recognize what is `new` in your invention over what other patents/applications you find out there. Goodluck!
(Not intended as legal advice. See the USPTO website, uspto.gov, for basic patent information and all the details you want!)