While Google's algorithm often does a great job of figuring out what you're after no matter what you've typed, you can make it do certain things that will help your search.
Many of the Search Tips in this guide can be adapted for use in Google. Consider the following tricks:
Google lists still more search operators in a Help article.
If you compare a Google search to a search in a library database, you'll most likely find a lot more sources. You'll also find sources with all sorts of purposes, from respected news sources to content farms. So look closely at what you've found before considering it as a reliable source for your research.
Take a look at our Criteria for Evaluating Internet Resources for some tips.
You might also just skip Google searching unless you are searching for something very specific. Instead, start with the websites listed in this guide.