When doing a keyword search it's a good idea to try a number of different search terms and phrases. Don't be discouraged if your initial keyword search brings back too many, too few, or irrelevant results--you'll want to try multiple keywords, synonyms for your keywords, different combinations of keywords, etc. to bring back the best results.
As with any search strategy, you may want to consider what keyword searching is most useful for and anything you should be cautious about when using this searching technique:
For example, if you are looking for information about the dangers of texting and driving you may start out with keywords like: texting, driving, distracted driving, danger, cellphones, etc.
But you'll also want to try using synonyms for keywords (e.g. cellphones = mobile phones, smartphones, iPhone, etc.) and combining keywords (e.g. texting and driving, distracted driving and danger, etc.) to get better, more thorough results.