What's notable about this mix is how it uses the stereo width. Only the lead synth (which has indeed quite a narrow frequency range with it's flute-like sound) and the bass parts are center, everything else is spread strongly to the sides. Not in the sense that instruments are panned hard left of right – that has been somewhat of a taboo since the 70's. Rather they are all “wide” stereo sounds to begin with. For instance, the clap sound appears to come almost from behind. That is probably achieved by using two completely uncorrelated signals for the L and R components (e.g. actually record both channels seperately, with in principle the same sound but no actual phase relation). Other possibilities to spread out a signal across the stereo canvas include:
- Boosting the S component (in an M/S basis representation) of an ordinary stereo signal, e.g of an X/Y recorded piano.
- Introducing an artificial phase delay on one of the channels – for instance, an actual time-domain delay (1~10 ms, no feedback or clean part), or an all-pass filter.
- Using lots of very short reverb. Perhaps ambience / gated reverb to avoid too much smearing.
Apart from that – well, EQ and compression do of course play a role, compression definitely a large one. But I think you have been taught a bit too much about “frequency separation” with EQ. It is a valuable thing to know about, and in particular it's good to develop a sense for which components of a signal aren't needed, when they interfere with other instruments, and how to rigorously prune away such components without disrupting the actual character. However, it's not in general true that you need to categorically keep apart which instrument “owns” which frequencies: some overlap is just natural, indeed essential for a proper harmony sensation. And in particular for everything percussive it's crucial that you allow for a wide frequency bandwidth, because only that actually makes sharp transients possible. (So much for Dirac delta function: the Fourier transform of that is just an infinite-lasting sine wave, quite the opposite of what's needed for a track like this!)