Opinions vary on whether Google Instant is a time-saver or very distracting. I hear Ross Perot's Texan twang--"Can I finish? Can I finish?"--each time Google anxiously starts returning search results as soon as I enter the first letter into the search bar. Thankfully, there is a way to turn off this feature, and the hardest part about it is knowing where to look.
First, click on the gear icon in the upper right corner of the Google home page, and then click "Search settings." You'll go to a Global Preferences page, where if you scroll down you'll see a Google Instant header. Simply choose "Do not use Google Instant" and click the Save Preferences button at the top or bottom of the page.
Google's main search page will then return to the look and feel it had before the company introduced Google Instant last fall. Google's autocomplete algorithm will still be present, helping you complete search terms, but to see the results of your query, you'll need to find the time and muster the energy to hit Enter.