You should ALWAYS mix at low volume (preferably through speakers) first. Check point 8 of my hints. 
So I was checking my vault on sunday and I’ve rediscovered another old track (created around 7-8 years ago) that was finished, but somehow sucked. I changed the kick in terms of the beat and I’ve adapted the mixing a little to my today’s standards. It still sucks mixing-wise (for instance, the TP value should be -1, but instead it’s -1.8 without any apparent reason, so I should recheck and most likely redo the mixing from scratch) and composition-wise (especially the beginning of the song respectively the buildup needs to be redone, but also the second half of the song). This is what it currently sounds like:
It was intended to be an Electro track, but it turned into an Electronic piece while composing.
What do you think?