Just a few starting places - potentially there are loads more. Let us know about the above, we can then move onto others. :)
Do you live in the country you are targetting?
No, I live in different country. However I have tried using gl=us after the url
Have you chosen to show on Search or just Content?
Selected Search
Do you have your settings set to show your advert all the time until budget is depleted? - where will I find this settings?
Have you checked in the Tools advert diagnostic bit? - yes
This keyword isn't showing ads
Although your ad is showing, its rank is not high enough to place it on the first page of search results.
I have checked almost 15 pages on Google