http://blogs.sfweekly.com/shookdown/2011/03/how_to_be_an_opening_dj_by_oak.php
1. Don't play a bunch of obvious hits early in the night. First of all, it's lazy selection to do that, and lazy selection is the hallmark of a poor DJ. Besides, the opening slot is the best time to be an adventurous selector (more on that below). Beyond that, you may be taking arrows out of the headliner's quiver. Yes, everybody loves that hot new cut that's tearing up the clubs. So then why waste it by playing it so early in the night? Leave it unplayed and let the headliner get to it at just the right moment where instead of liking the song, the crowd goes berserk for it. Understand that the headliner is going to be starting where you leave off, so if you're already running a bunch of sure-shots, where is the headliner supposed to go from there? Build the energy up slowly.
2. Play the appropriate music. My friend's opening DJ was playing shrieky, fist-pumpy techno before the clock had even struck 11 p.m. My friend -- not a shrieky, fist-pumpy techno DJ by any stretch -- kept wondering, "Why doesn't he play some Tribe Called Quest? Some James Brown? Get people loose like that?" And fortunately, the relief opener did just that, but that first DJ failed to tailor his selection appropriately, and the party suffered for it.In this day and age, there's no excuse for not doing your homework on who the headliner is when things like Google and YouTube are right there at your fingertips. Learn about who you're opening for and adapt your set to the headliner's vibe. Versatility is the calling card of a quality DJ! A good opener should have some familiarity with the headliner and should be able to play a set that will allow for as seamless a transition from opener to headliner as possible. (Side note: Promoters bear some responsibility here as well, as they need to pick opening acts who are appropriate for the headliner. Don't just put your homie on, promoters -- put on the guy who's qualified to do the job!)
3. On the subject of versatility, treat the opening spot as an opportunity to showcase the depth of your knowledge and your music collection. Take the chance to play some great, obscure tunes that you probably couldn't play to a packed, enthusiastic dance floor. To me, that's one of the joys of being the opening DJ: You get to nerd out over music in front of a crowd and throw on those lesser-known cuts that you really love. Embrace that opportunity!
If you do your job and do it well, you will get noticed. The headliner will be much more likely to shout you out on the mic -- "Give it up for my man DJ Blahdy-blah, he did his thing earlier!" And the promoter will notice, believe me, which can only work to your benefit. If you prove that you're a capable professional, you will get put on, and the more you get put on, the easier it will be for you to be the headliner down the road.