The key to unlocking its full potential is to do more than just typing in the keywords you want to target and seeing what follows afterwards. This is because your chosen keywords might be anywhere in a commonly used search engine query, even at the end.
Use it constantly and you'll see that there are many general verbal templates that appear over and over again. Take "the best (insert keyword) in (insert keyword)", for example. People also look for the cheapest, the worst, the biggest, etc. And that's just the start.
Think of just about any oft-used phrase, with or without a question mark, and start typing it in. You're sure to get numerous suggestions.
You'll often find ones related to your city or area. And even if you don't, there's still a good chance that people do make such queries from time to time -- just not as often as those that do appear as suggestions.