Looking through the logs of the cache listing, there are several cachers that made several trips to find it and it went missing back in March. This cache may be a bit harder than it's rating.
You could do a couple of things.
Try doing a few other caches until you get used to the GPS and the search.
Add it to your watch list and wait until someone else finds it so you know it's there.
E-mail the owner or the previous finder for a hint (that spoils the hunt, but it is an option)
Keep trying - I have one that I've visited 8 times and still haven't found.....
Good luck!