Many beginner DJs have the issue that they practice for 30 minutes to an hour each day. This is not a problem for developing skills and mixing technique, in fact being able to mix many songs in a short period of time will increase your speed of mixing and rapid beatmatching. However, if you expect to do a normal set in a club, chances are you'll be playing for 4-6 hours. The likelihood is, if you keep mixing at a fast rate, you will be out of songs before most people even hit the club. Here are my tips on preparing yourself for a long set and ways to increase the time you can play for.
This is the most obvious, and the most obvious point. If you don't have six hours worth of music, you won't be able to do a six hour set. As a rule of thumb, aim to have twice as many hours of music than the set length. This is mostly due to the fact that you are not playing tracks end to end. You will be mixing into and out of songs, meaning that a song is never played through it's entire length by itself.
The other reason to have more hours of music than you need is because not every song will be appropriate for the night. If the crowd isn't ready for some of the harder dance songs, you will be able to go with their mood, instead of forcing a BPM and energy increase on them.
Another rule I go by, is having several hours of "warm up" music ready. Remember that people often arrive at the club many hours after the DJ starts playing and not having enough warm up material will really kill the mood for people who aren't yet ready to go all out on the dancefloor.
Conversely, you don't want to start off too slow. When the crowds arrive, you want to have a few people already up on the dancefloor - there is nothing worse than walking into a dead club. This is where you can mix in some of the slower tracks which are popular. It is also a good time to throw in some more vocal tracks or even, if you are willing to stretch that far, take a request or two. Once the dancefloor is packed, you have much more leeway to play "your" style but to get there, you sometimes need to please the early arrivers so they aren't scared off!
2. Try Finding Extended Mixes
The greatest way to extend your mix without adding too many extra songs is to use extended mixes. A good extended mix lasts several minutes longer, if not more, than the radio version of the song and so will give you more play time per song.
In the 1980s, disco and dance artists often released tracks on 12-inch singles. These were typically extended mixes that lasted often more than 10 minutes. Songs such as "Funky Town" were at least double length compared to their radio releases and explored the track much deeper. Sections were often longer and took more time to develop.
One of my favourite uses of extended mixes such as "Funky Town" mentioned above, is to quietly layer in a loop of the intro throughout the duration of the song that it will mix out from. That iconic cowbell rhythm will get the more music savvy people geared up to expect it, and those who don't will subconsciously be familiar with the track's beginning before it's even played full blast.
These extended mixes are great for long sets as they often give the audience new experiences with songs they already know. There may be extra verses which they have never heard and the build-ups to the drops and choruses take longer than they expect causing more tension and anticipation.
Another great trick with extended mixes, especially with instrumental songs, is adding acapellas over them. With extra length, you have more time to mix vocals over the song and remix it live without worrying how soon it will play out.
Finally, on this point, an extended mix is a great opportunity to catch your breath, and maybe even run to the toilet or bar. Just make sure you have a trusted friend there to protect your gear from that one drunk girl who thinks she's a DMC champion and who will inevitably try and nail her first "scratch" routine.
3. If You Can't Find One, Make it Instead!
It's not hard to make an extended mix, either before the set, or during it. By using cue points and loops, you can jump back to choruses and extend the intros/outros. Software such as Serato's Flip allows for this sort of editing in preparation however it is simply a means to make it easier and more complex.
By using software controls such as beat jumps, you can jump back by a set amount of beats, in a similar way to looping to squeeze some more length out of your tracks.
Depending on the song, extending it may be as simple as allowing another build and drop after the final one. Be cautious however, some crowds won't like the same song lasting too long so make it smooth and appreciate that not every song will work with this trick.
If you have audio editing software, you can produce your own extended mix of the song. Make sure you are using the same kicks as the song and keep it in the same key. It can be as simple as adding 30 seconds of drums to the start of the track, or as complicated as remixing large sections of it.