If you choose poor keywords you are going to get poor Adsense conversion. It is as simple as that. If you are tired of getting a penny per click, then look into what keywords you are using. If you want to have higher Adsense conversion rates it is going to help for you to find those keywords that are going to bring you higher Adsense revenue per click. You can make money with Adsense but how much depends on how well you use it.
What makes Google Adsense and Adwords so beneficial you aren't just shooting an advert to millions who aren't going to be interested in what you are trying to advertise or aren't likely to buy. You are able to customize an ad just for them based on where they are going on the ad and what they are interested in. That is what brings the high Adsense conversion rates.
Google is able to know exactly what a person is interested in based on the content of the websites, the frequent use of the keywords and allows you to capitalize on that. Google looks out for certain keywords and phrases and chooses for them the images or ads that they will be interested in. Used in the right way this can be more effective and efficient than the biggest, flashiest commercials on television.
The most expensive clicks are not necessarily the best. You will find some keywords that have a very high pay out per click, over $40-50 per click, but what good do those do you if those are rarely clicked. It doesn't matter how good you are at optimizing them, they just won't help you make money online all that well. Find words that people click a lot. It doesn't matter if they are under $20 or maybe even less than $10 per click. If you have thousands of clicks on those keywords, that is going to make you thousands more a day than those high pay out clicks that no one is really interested in. Use Google Trends or the Google Adwords Keywords tool to find words or phrases that are popular.