I think there are basic rules on mixing…like mix at the beginning of a 32 and make sure things dont clash…like vocals on vocals…or same sounding synths…and if you are mixing at synths/vocals…you need to make sure they are in harmony…these are basic rules for mixing, that has to be followed pretty much by every DJ…how you eq…and what you want it to sound like is very specific to each DJ.
As well speaking from an EDM perspective…each genre has different styles of mixing…Progressive and Trance i find are very similar…where its more about cutting out your highs and mids and blending…where as Electro/Bass Music is more mids and well BASS…I find with prog/trance…the basslines are very similar from song to song…with variations here and there but the highs and mids are very different so you have to blend/swap them more.
There are special cases…and my buddy who is a GREAT drumstep DJ likes to tweak his highs and mids more than the bassline.
Again this is very dependant on the DJ.
The easy part is finding out where to mix in/out…the hard part is effective EQing…again this is all just my opinion