My friend Illuminatus recently reviewed 8 Steps to a Pain-Free Back by Esther Gokhale, which seems to be a great book on improving your posture and preventing back pain. I have read his review with great interest, and checked out the freely available YouTube videos.
So, if you spend a large part of your day sitting, then check out the review. It may help.
In his review, Illuminatus also draws attention to the fact that attraction and posture are linked, and you tend to view somebody with great posture as more attractive. I know that many people have problems "implementing" some of the absolute basics. Thus, have a look at the review.