if you mean adsense placements do it in the upper content section and make it looks like it belongs to the content
To get the best Adsense CTR, place the ads right below the post tittle, inside or right below the content. Blend the color of the ads with the content.
I have tried a few but I think the top and right sidebar is the best, the size that I have tried are 468x60 banner and 336x300 rectangle on the right For placement u will always need to trial and error to optimize it
I find this color coded heat map helpful: http://support.google.com/adsense/bin/answer.py?hl=en&answer=1354747