I'm just going to list a few things, try not to take any of this too hard. I just find that criticism is the best way to improve.
For the first track:
1. I don't like the intro (From 0:00 - 0:10) I feel like it would be better just to start the track at the 10 second mark, or make a different intro
2. You should add bass and sub-bass to the entire track, but particularly the portion before the drop. It feels really empty.
3. Your snare feels kinda weak, I suggest you layer some other samples with it, or swap out the current sample, or both.
4. Hats. You need them. Adding in a cool hi hat rhythm can do wonders for making your drums more interesting.
5. The bell-ish noise you have in the part after the drop is weird, and doesn't really fit.
6. I suggest having a breakdown mid song, and a longer ending.
Remember, all of these are fairly small problems, and its a hell of a lot better then what happens when I try dubstep.

Unfortunately I don't really have time to give any suggestions for the second, but the best tip for improvement is just to keep making tracks.