For my Adsense ads, I used the official Adsense plugin but the plugin didn’t allow me to place ads in the sidebar. I googled the problem and was not able to find a solution. In order to get a rectangular ad in the sidebar, I dragged a text box into the sidebar widget area and then cut and paste my adsense code in there. I made sure I only had two other ad units with the plugin since there is a three ad limit with adsense. You need to check the ad placement with all your page styles (home, posts, and pages).