Are you SURE you have the best keywords?
Have you checked the keyword planner tool?
Did you use different patterns of words?
I just did a video that will show you some examples of the best keywords, plus show you how to find MORE of your own.
Check them out in the video.
P.S. The wrong keyword choice is one of the most EXPENSIVE mistakes I see when I audit an Adwords account.
PLUS if you use the right keywords it can make your SEO easier.