Creating smooth transitions is determined by a few factors, including the keys, tempos and melodic content of the tracks. If a DJ is mixing together two tracks with vocals, a good use of cue points would be to place a marker where the vocal begins in the track. The DJ can use these cue points to bring in the next track so that the vocals do not overlap.
Placing cue points can help a DJ to make mix choices. For example, if cue points are placed at the beginning of the verse, drop or chorus, 2nd drop or chorus, or outro, this will give you four places where it would make musical sense to begin a new mix. A DJ may have a track that has a great intro, verse and drop but then a breakdown that they don’t want to play. Setting mix in and mix out points on a track like this allows them to play the parts of the track they want, but cut the track before the breakdown section.
During the heat of a live mix, it may be easy for a DJ to lose themselves in the moment and forget to mix out of the track exactly as planned. The cue point serves as a reminder to mix in the next track at the intended place. It’s worth mentioning that setting cue points does take additional preparation time.
To save time, a program such as Mixed In Key can be used to automatically set cue points and then these cue points can be imported into Traktor.