here is a personal tip of mine on the shadowbox work...

yes you must create a boxer in your mind to spar with when you shadow box hence the term. i would like to spar some of my favorites: dempsey, monzon, sharkey, leonard (benny) and my not so favories chavez, whitaker, pryor, hearns -- whatever, the point is that this made the work fun for me and made me use my brain. so often the fellows at the gym like to treat this as busy work and as a result they never learn. it reminds of a kid held after school, forced to write some 'i will not...' sentence a thousand times over on the black board. he does it mindlessly, his soul somewhere off in the clouds as he pains himself through the movments eager to stop, looking up at the clock hoping and praying it would hurry the hell up.

another one is i would often adopt the style of a typical mexican or standard dim-wit amateur and box an imagined version of myself. i did this to understand what they saw as they fought me so that i may better know how to manipulate them. you see you must always box from the perspective of your opponent, by this it is meant that you must envision what he sees, what he thinks, the way he moves. you use this information to set your traps. so when i adopt the soul of my opponent and try to shadowbox myself it would put me more and more in tune with their perspectives and as a result more and more in tune with what is needed of me to beat them.