finding the best appropriate place on your blog or site to place the adsense is fine but its completly pointless unless you have daily visitors to your blog or site and the ones that do are only there for a minute or 2 read what they need and then go unless of course a google add catches there eye and they actually click on it but the CTR is still going to be low unless people are doing that every day in there droves.
Been having the best luck with a square/rectangle on the post itself, near the top. Left'll probably get you more clicks but visitors'd prefer right side. Gotta care about them if you want them to come back