By default, Gmail returns 20 results per page when you perform a search. If you'd like to bump that up to 50 and spend less time paging through results, you can change one simple parameter in the URL or, better yet, use a simple bookmarklet.
Writer and programmer Joe Reddington shows us that you can force Google to return 50 results per page by replacing "#search" in Gmail's URL with "#section_query". If you don't want to have to edit the URL manually every time you need more results per page, you can use drag this handy bookmarklet to your bookmarks bar and click it every time you need more results instead.
Bookmarklet to make Gmail return more than 20 search results. [Joe Reddington via Reddit]