Actually shinedown's idea about covering his cards is an interesting one... I admire his creativity, BUT - I feel that if you want to develop quick reading abilities under pressure about possible hands, you need to play, play, play and practice this discipline while you are playing - so my suggestion is playchip games - actually I recommend this to everyone of you.
Anytime, I need to educate myself or develop a weakness of mine that I notice in my game - or I want to try a new poker strategy
or theory, I will take it to the playchip world and practice, practice, practice... raising strategies, Dan's mathematical approach, Gus Hansen's theory... Hellmuth, Brunson... all of these I have applied and played in playchip land. A lot of poker players do - there a number of Full Tilt Pros who are in the playchip games and if you ask them why it's the same reason I have - practice and development... It's good training for handling bad players too, if you can win consistently with a strategy there then you can play it in real money
(I believe, but then if you fail and need further development I would go back and work it out back in playchip world..)
Just a thought... Personally some of Harrington's theories don't always work super well for me in certain games with different players style... I'll try to describe that later - I still think he has spelled out the Science of Poker better then anyone else who's published a book though...