The easiest system for DJs to incorporate harmonic mixing is the Camelot Wheel. This wheel shows you the strongest connections to make for each type of key. All you need to do is work out what key one track is, and then you can see which other keys will match well. There are potential keys Pay attention below ⬇️

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  𝗗𝗶𝗴𝗶𝘁𝗮𝗹 𝗔𝗿𝘁𝗶𝘀𝘁 𝗔𝗻𝗱 𝗔𝗜 𝗗𝗲𝘀𝗶𝗴𝗻𝗲𝗿

It's impressive how music theory can be applied so practically.