I have asked in another thread why your ads don't show. Let me ask the opposite this time: Why do your ads show? What do you do that Adwords works for you successfully? Any advice?
Many times the reason why your ad doesn't show is because your min bid is too low. Try raising it. Another reason is sometimes newbies get carried away with the use of negative keywords. And finally, maybe nobody is searching for your keywords.
The best thing that I did was take all my broad match keywords and make Phrase and Exact Match lists from them. Three things happened: 1. My CPC decreased 1-2 Dollars a click. 2. My CTR went from 1-2% to 15-20%. 3. My ads stay in the upper left hand of the screen.