These are usability tips for implementing search functionality on your site. Implementing these tips will insure a more successful experience for your users and these tips are backed by research.

Search Pages 

• Put the search box in the top-right (or less optimal top-left) of the homepage and every other page.
• Use a form button labeled "Search", not a link.
• Make your search box at least 27 characters wide. If you want to future-proof your design, make it 30.
• Skip "Advanced Search" because less than 2% use it. If you really want to offer it, put the word "Advanced" on the results page. No one uses the advanced search before using the general search.
• Support the use of quotes for a literal text string.

Results Pages

• Mimic Google's result page. Everyone is used to it already so don't fight it.
• Use "Next" and "Previous" page links instead of numbers which are generally too small.
• After a user searches, keep the query words in the search box.
• Add "Best Bets" to your results pages. Construct them for your most frequent queries (check your logs).
• Allow for "Sort by Date" and skip other types of sort.
• When no results are found, return a page that says "No results found" keeping the query words in the search box and a link to your Advanced search, if you have it.