These create a wide variety of undesirable problems for search engines. The information contained within the page title should provide a descriptive summary of the page content. Keep materials not intended for publication off of the web server. Your main web directory is not a place to store old versions of your site, outdated HTML pages or incomplete documents. A common mistake is to store this material on your web site and assume it's not getting picked up by search engines because you haven't linked to it.
Every misspelled word is an opportunity missed if someone is searching on that word.
Consider the design of your site in relation to keywords on the page. If your pages are primarily graphical there's little chance it will be found on a search. Words you think your audience will use to search on should be placed near the top of the document for best results. These are only a few basic recommendations. For addition questions feel free to contact a member of Internet Development.