oh yes...you can 'design' your thinking. It takes a little work, but there are different 'technologies' out there to help you do this- neuro-linguistic programming, cognative/behavioral therapy just to name two off the top of my head (look into NLP, the stuff works!)
IMO, it all boils down to creating/enforcing new/different neural pathways (habits)
Dunno if this will change 'personality' though, -although there is a bit that can be done to change temperment (emotional range/norm) through proper nutrition, exersize, nootropics, sleep etc.
Throw in a regular medative practice so's that you can learn just how your consciousness works for you, and youll wake out of mechanical behavior in no time!