Related to this, a good friend of mine is the engineer for a very well-known dub producer, and last time I saw him I ran through a live set I've been working on for a few months - (I make jungle/breakbeat/IDM stuff). He gave me two great tips - one of which I can't be bothered to explain here as it'll take me to long to type out, but the other was basically saying the same thing as this - make some elements really jump out of the mix, make stuff BANG and it'll make the audience respond so much better than having everything sit nicely and politely throughout the whole set.