Hmm ok Im quite opinionated on this one ... however I think primarily tune selection is always gonna be the first thing however I guess where you may get a diff response out of me than many other on here is I like to see something technically interesting being attempted in a mix or at least some defining individuality. You say that...
many will wanna smash the boundaries of routine standard mixing
Youd be suprised in fact at how this isnt really the case [most definitely in the psy scene]. If folk are trying to break boundaries theyre ususally doing it via a live set rather than dj'ing. Imo the avg set involves just stringing 10 tunes together and thats your lot oh and if youre really lucky someone might throw a lord of the rings sample in for good measure. Don't get me wrong, Im all for being taken on a journey but theres making an effort and theres doing the bare minimum.
Its kindof like guitar say ... anyone can pick it up and learn to strum a tune - but how many people play with say the skill of hendrix ? [this is maybe a bad analogy but Im trying!]
So I guess my advice would be not to limit the music you listen to or play, try *everything* musically/technically, dont play the same old thing as everyone else and at the same bloody time too [night time/morning tunes .. pfft!].... and most of all *have fun* !!!
I guess my approaches are those above ... I try not confine myself and Ill do anything from mixing stuff up at the wrong speed, scratching psy trance, doubling up copies of yellow submarine

... oh and youre not a dj if yove never drilled an off-centre hole in one of your records :P
.. sorry you caught me on a subject close to my heart on this one !
peace,
m