A good way to get the hang of it is to start with the pitch fader from the incoming track set to min (or maximum, but I prefer speeding it up = clockwise nudging rather than slowing it down, but that’s a personal choice I guess). Assuming you have developed the habit of “guessing” the BPM by listening to it at normal speed first. This should tell you if the next track is within “mixing range”.
You now know the incoming track is way slower than the playing track.You don’t have to worry about “hearing” which track is the slower/faster one, you already know. Now play the new track on the downbeat. Listen to it become unglued really quickly. Dial up the pitch fader, don’t go halfway, but don’t do mousey steps either. Repeat play and listen to the speed at which it drifts. This tells you something about how much extra pitch you need. At some point you will notice that the drift becomes less pronounced and slower. At this point you want to play the track on the downbeat and as soon as you hear it drifting, nudge (outer ring of the jogwheel) quarter turn (or half if you think it’s still a pretty big speed gap) clockwise with a quick movement. Listen if this improves the sound (makes the gap smaller), which it should. Now adjust the pitch again. Keep repeating this process. The nudges and the pitch fader adjustments will become smaller and smaller. The moment you hear the drift and the amount of drift get closer too.
Finally you will arrive at a point where there is so little drift, that you can make your mix comfortably, with perhaps one or two small nudges during a long transition.
It sounds like a lengthy process, but you will get it down quickly once you get the hang of it.
Greetinx and good luck practicing,
Chuck