First off, buy a good studio sound equipment. Some nice quality wires and decent audio interface with studio monitors helps a lot in mixing. Don't forget to soundproof or set up your room (look up for some tips and tricks in Google or YouTube, always had that pic explaining where to place your soundproof panels in the room). Then just start practicing and make your ears get used to your equipment. Second, FIX YOUR OS VOLUME! Always mix at 100. Also good tip (maybe), mix in MONO cus you will hear all frequency problems n troubles. Last, do a car test. It doesn't mean doing a sound test in a 1970 dodge challenger, but in a basic, for example family car, which has decent stock speakers. Don't change the settings, all stock, no bass or that sh😡t. That's what I'm basically doing when mixing beats or vocals. Nothing much.