computer777 – When I read his books I worked on internalizing them, thinking about how his words apply to me and how I can change. It really made a big difference. The books I personally found most useful in that way were:
When do the good things start – for a good intro to personality types
Life’s too short
Self improvement? I’m Jewish
Angels don’t leave footprints
He also deals with bringing more meaning into your life (spiritually) which I found helped tremendously in giving me an understanding of what our role is (and isn’t) as people, and how to turn to Hashem for strength and approval. I see this step as important in supporting you while you grow/change. My favorite books in that category are:
The enemy within
Dearer than life
His Haggada is also amazing.