add heaps and heaps of relevant good keywords relating to each ad: this is the key to get the cheap ones; instead of getting 15 clicks for $7 you will get 70+ per day.
reduce the max cost per click to 18 cents, anything over 45 cents is not worth it...(may as well push the 5 and 10 cent ads hard and leave the 70c clicks...). do a review in 2 weeks (when keywords have statistics) at this time make sure your getting lots of click; and change max cost per click to 14 cents; and change some of the Premium key words up to 20 to 35 cents manually (it tells you how much the Premium key words are when left running).
comment: ad group keywords should relate to ad only... ... group ad's need keywords to run...