sound material selecting is the most important thing, when creating a good track, no mixing and mastering can fix a track where track elements just dont want to go with each other.
sometimes its also better to with less elements, but when they fit with each other its gooing really well.
one rule sticking for me was that a supersawish pad and a wide lead wont go with each other. or a thumpy kickdrum with a big Reese Bass.
these examples aquiring the same frequency space, the supersawish pad and the wide lead have live in the same M/S Space.
a supersawish pad and a prog pluck would fix it. enough with the examples, i hope you get the ideas.

this stuck in my mind, it helps to understand mixing and therefore to get a picture about sound material selection.

i dont get it why everybody is going to smash its tracks as loud as they can, remember its not good for your ears and your listeneres ears.

hope you keep in your mind, producing loud isnt also better for your ears getting tired and also that you could harm your ears. keep that in your mind if you havent thought on it already.