A few thoughts on that latest one:
Try boosting your kick at about 100 Hz, its a little weak.
Also, all your levels are a bit low - like, I play a song in itunes and then I put yours on. Its the same volume on my computer but waayyyy quieter.
Try using a combination of compression, limiters, and a maximizer. Get all your levels really low then boost the fuck out of them.
Dada Life's sausage fattener is good for this kind of stuff, and stupidly easy. Its all over torrent sites too.
I think the song could really benefit from some material to fill it in - ie, chords, some more bassy sounds.
I like to think of producing beats like working with a band - you need to orchestrate your parts so that they fit together, complement each other, and fill in the frequency spectrum (don't get too caught up in that last part but if you want to have a dope chorus it needs to sound really full generally).