it doesn't matter what style you start with. whatever style you play, figure out what the key sounds are, and focus on listening for those in the mix, and ignoring everything else.

mixing the kick drum can actually be difficult if the kicks of the two records sound alike, especially with slower, fatter beats, like house, because your beats will have to go waaaay off before the kicks stop overlapping and you notice the difference.

in breakbeat or drum & bass, it's easiest to mix if you listen for the snare drum on the back beat. in 4/4 styles the ride cymbol is usually pretty easy to pick out.

basically, for each mix, pick a sound that you can easily identify from each record, then listen like crazy to keep track of those two sounds. really try to keep them seperated in your head, even when they are coming out of the speakers together. the more you practice, the more you can listen for without getting lost in the mix.