Andy Touchfingers mixes his fully keyed,fully prepared dj mix. As you will see in this video, each of the tracks go together well and the sounds complement each other musically.
You may also learn how to expose and hide different elements of each track if you watch and listen closely.
Andy also explains that the second track has some strange drops that might not make the two tracks a perfect match (although they were perfectly matched MUSICALLY).
For the next track in the mix, andy goes through the circle of fifths chart to help determine what is the next track that would be in the best key to continue the mix. After you figure out how to do it once, you can plan out the rest of your DJ set by the keys of each track!