Ive entered a couple of competitions before and got through to the finals, the best advice i can give you is, be original if you can make some remixes up tracks. Use samples and loops that you have produced! Also I used to make up Opening sequences of sound effects, samples, bit of tracks make it fun.
Also have some balls of steel, I was in the same sort of set up in a comp and all the other competitors before me had been playing banging trance, hard house etc all night, now i dont play this kind of stuff so I walked up I let the host introduce me over the last guys banging trance track left it for about a minute then just turned the turntable off asked the LJ to put the lights to black and left it for about 30 seconds with silence, people started booing clapping then out of nowhere I dropped a bootleg version of Austin Powers Vs Fatboy Slim’s Rockafeller Skank that tied with the LJ bringing up the lights the floor went off the hook!
That got me through to the final! lol
Be yourself and play what you know but give it a bit of show boating, People will always remember a moment!