Reply to Getting into Mixing Dubstep

So I've started seriously trying to practice mixing dubstep lately (probably not the best genre to be starting out on) with my copy of Traktor and crappy Midi keyboard. I have a good idea of what I'm doing with phrasing and such, but have two main problems that are really holding things back:

1. Track selection - I have mainly been using compilations and a few favourite producers to get tracks - I then decided to sort these according to some rough moods/subgenres (chill, jump-up, heavy, melodic), and in a 1-5 star rating system within these subgenre crates. This is good and all that it organizes my music a bit, but sometimes it just doesn't work for me. What am I doing wrong? Should I try and just "feel" what track to play and have more of an organic process than following a system of basically numbers? Or maybe my tracks are the problem - for instance the "chill" crate seems to be sort of all over the place.

2. Mixing out a track - A lot of the time when I am mixing two tracks and the blend is a very full sound with much of the frequency spectrum filled with the many instruments of the two tracks, removing one just sounds dumb unless the new track is somehow just way bigger. What is the solution to this? longer blends that fade out the old track using effects? I don't really know what effects would be good to use - maybe delay? I end up using the filter quite a bit.

Some tips would be great - I feel like I could use some more depth and personally discovered music rather than compilations, but I also don't want to blame the problems on the tracks!