I assume that you do have something to sell on your blog, whether it be your own product or some affiliate product. The most targetted traffic you can get is through pay-per-click ads. Here, whoever clicks on your ppc ads would presumably be actually interested in what you offer, and would thus click on them, get redirected to your blog and hopefully buy what you want to sell. The drawback is the costs involved. For example, 4 - 70 cents/click x a couple of thousand clicks a day = a princely sum to pay Google daily. And if the only thing you are doing to monetize your blog is through adsense ads, chances are pretty high there will be a substantial nett loss daily.