have your song start off in one "room" and move to another...
www.myspace.com/nymantics
listen to "world collapse." when i wrote this i was trying to picture a house through which the listener was walking. i made it solely on the mpc and with records.
don't get too hooked on your one sample. find something that matches up with it and transform from one to another. change your drumset, go to halftime or doubletime. make a bridge with a vocal sample to a completely different part of the song. in other words, try and back out to get a better look at what you're trying to do--when you make a beat you're reading too closely, 1 line of a whole page. better to slide back a little.
i know exactly how you feel, it's frustrating as hell. however, if you make it a goal to make SONGS rather than BEATS the results will get better and better.