In this video Frederick Vallaeys, a former Google AdWords Specialist answers the question on how can an advertiser get AdWords to show their ad for low search volume keywords. You can view the video here. http://www.youtube.com/watch?v=BWkO_O2f3NE&feature=youtu.be
Here is my own recommendation on what to do as I don’t agree that broad match keywords are typically best for an AdWords account.
1. If Google has been turning of or not showing your ad for keywords that you really like that are over three words long, try first shortening the phrase. Take a phrase like pest control services in Tom’s River New Jersey and use pest control Tom’s River. Better yet I like the phrase +pest +control +Tom’s +River or +pest control +Tom’s +River. Use broad match modifiers first and test your response with shorter phrases and a + directly in front of important keywords to get more activity.
2. If keywords are not tagged as low search volume keywords, you may have keywords that are simply out of the auction and raising the bid may help them to show.
3. Cut your long tail phrase from five or six keywords down to three or four and use phrase match.
The key in all these cases is to test, test, test. If you still cannot get your keywords using broad match modifier and a shortened phrase to show, then I would but the query and move to full broad match. Watch carefully your search term report and aggressively add in negative keywords to keep your response highly targeted.