To be a true DJ, you need to have a real passion for music and the way it sounds, both in isolation and in a sequence, as well as an understanding of what the artist was trying to achieve.
Many years ago I obtained a Bush Audio record player (complete with double tape deck) from my grandma, to go with my cheap Richer Sounds pitch variable second hand record player – this was the very difficult beginning of my passion for DIY mixing. It was amazing what could be achieved with 3 little EQ sliders and cross wiring the two very different record players into the tiny 3 watt speakers, just because I was fascinated with the idea of continuous back to back music. I played everything from Pink Floyd, Boney M, Blondie to Mozart; anything I could get my hands on as long as it would go through the speakers...better still if it was on vinyl and stood out.
I spent my school days listen to Pete Tongs Essential Selection on the cassette tapes I had religiously recorded on Friday evenings.