Learning how to use a DJ mixer can be every bit as complex as learning how to play a guitar. On the other hand, it could be every bit as fun. Once you get to know all the channels, knobs and sliders on your mixer, you will be beat-mixing and blending in no time.
Use the DJ mixer's cross fader to go back and forth between the tracks you are playing. To do this, simply move the slider to the left (to play the track on the left turntable) or to the right (to play the song on the right turntable). Put the slider in the middle to play both tracks at once.
Use the fader curve (usually located underneath the cross-fader, although sometimes it's beside it) to adjust how your cross-fader will go between tracks. Figure out what kind of mix you'll be doing before your live set, then turn the curve knob accordingly. The closer the knob is to the minimum setting, the slower and smoother the transition will be. Nightclub DJs prefer this option because one track literally fades into another, creating a smooth, danceable mix. The other option would be turning the curve knob to the maximum setting, which will cut one track straight into the other with little or no transition. Turntablists prefer this option since it will go from one track to the next with great sharpness and precision.
Use the equalizer (or EQ) to adjust the different sound levels of your tracks. The EQ should have three sliders marked "Lo" (for the bass), "Mid" (for the vocals and melodies) and "Hi" (for the handclaps and snares). Pushing any of them up or down will increase or decrease their corresponding sound level. For example, if you turn the "Lo" slider all the way down, the track you are playing will be all treble. You'll often hear a DJ turn the "Lo" all the way up and drown out the other sounds in the live track to create a breakdown transition into another track.
Use the gain knobs (usually located at the very top of your mixer) to keep the inputs coming into your mixer at a constant level. The tracks in your mix will have different volumes and frequencies, so you'll need the gain option to stabilize both. There should be an LED screen on your mixer that will show you the sound signals coming from your tracks. Play with the gain knobs until you get the signals almost in sync with each other. Once you've done that, you don't have to worry about the cued track (the track you're bringing into the mix) being any louder or quieter than the live track.
Use the vertical volume sliders (also called "channel faders" or "level control") to increase or decrease the volume of the music that you are playing. If you are using your gain knobs correctly, the volume sliders will stay parallel.
Use the heaphone monitoring selector to preview the cued track through your headphones. There should be a button ("Cue 1" for one turntable and "Cue 2" for the other) that will send any audio signal from the corresponding turntable straight into your headphones.
Some EQs are represented by knobs instead of sliders. This doesn't really change how they work though: Turning the knob to the "max" setting will increase the sound level, and turning it to the "min" setting will decrease it. The "max" and "min" settings on a fader curve may be represented by two drawings: the "X"-like drawing is the "max" setting (for the turntablist method) and the straight line-drawing is the "min" setting (for the nightclub method). Every DJ mixer is symmetrical. It will have the same number of options (EQ, volume, gain) on each side of it to correspond with each turntable.