If you're currently making money from CSE with AdSense, here are a few optimization tips to help you improve your current performance. (If you're not already earning money this way, scroll down to learn more about how you can start doing so, using your search box.)
1) Search box placement: Search boxes should be easy to find, typically under the header or on the left navigation bar, to encourage users to simply search for what they're looking for instead of spending time browsing through your content. Try to keep your search box in the same place on every page so users know where to return for future searches.
2) Two search boxes per page: For pages with a lot of content, we recommend placing two search boxes per page - one at the top of the page where users can immediately go to to find what they're looking for and one at the bottom of the page where users can quickly search for something else after reading the content on the page. You can track the performance of each by creating a custom channel.
3) iFRAME: By choosing to host the search results, you can integrate search results and ads within your site so users don't leave your site when they perform a search. If users don't find what they're looking for in the search results, they can easily click to another section of your site through your site's template.
4) Search box on search results page: Remember to place another search box on your search results page in the case that a user wants to perform another search.
5) Ad placement: For better monetization, we recommend choosing to place ads at the top & right of the search results for added visibility.
6) Appearance customization: Customize the search results with your site's colors to match the look and feel.
If you aren't using AdSense, we encourage you to sign up and get paid for every valid click on ads you're already showing. Just go to the Make Money link in the CSE control panel and fill out the short form to sign up for an account. If you already have an AdSense account, you can easily link the two to start earning money immediately.
Now then -- better go figure out what to buy with all that extra cash. ;)