Listen to music through your headphones and differentiate each instrument and element of the song. Start by choosing simple records, and pick out the bass, snare, kick drum, etc.
Put two records on and adjust the crossfader so you can hear record 1 through the speakers. Set the 'cue' controls on the mixer so that you're hearing record 2 in your headphones. Hold your headphones so they're only covering one ear and, you'll be hearing record 1 with one ear, and record 2 with the other. Try to differentiate the two while listening to them both at the same time.
Put two different records on at once and decide which one is faster. Adjust the speed of one of them with the pitch control, or by hand to slow down a vinyl record. Do this little by little until they are both in sync. This is known as beatmatching.
Put two different records on and listen to them in your headphones. Set the cue control so that record 1 is in the speakers. Follow Step 3 in Section 1 to beatmatch the two. Move the crossfader to the middle so that both records are playing from the speakers. Then move it to the left so that only record 2 is playing. This is called a blend.
Listen to two records in your headphones, with record 1 in the speakers. Wait for a percussive break in record 1, then bring in record 2. To mix the two you can either blend them or beatmatch them as described in the previous section. You can also do this at the end of a chorus, particularly if you're mixing hip hop or breakbeat.
Listen to two records in your headphones, with record 1 in the speakers. Beatmatch the two as described previously. Listen until a point comes when you want to switch records. Move the crossfader quickly so that you are now hearing record 2 in the speakers. This is called a 'cut' and is handy if the two records clash. Cuts are also typical of breakbeat.