Usually the longer you make your keyword phrases, the less money you'll be bidding for it. And you'll be able to focus your ads more.
For instance - If I'm searching for a "red widget" and I see one ad for "widget" and another ad for a "red widget" - I'm going to click on the ad that says "red widget".
The key is to split up those keywords, into as many keyword phrases as you can, that still pertain to your website. And then create focused ads with those keyword phrases. If you want more people to click on your ads, you have to give them exactly what they're looking for. And since you're not a mind reader, it's best to have a lot of keywords, and ads to match.