Most of the time, when we're talking about editing in music production, what we mean is to arrange audio or MIDI clips to make them sound a certain way. However, this is not the only meaning that editing has.
The second, although often overlooked way of editing is to make sure that anything in your track serves its purpose and is necessary to complete it.
Edit, Edit, Edit
Anyone who's gone to art school has heard the credo over and over. Edit, edit, edit. And what our teachers or professors meant with this, was not only to (re)arrange everything to convey exactly the message you want, but to also make sure nothing's superfluous or at worst works against your piece of art. My favourite prof at uni always asked one question: Why? It could be bloody annoying to have to explain the reason for everything. However, it taught me so much, because it made me think and crystallise why I did what I did or what I could do better.
A lot of music producers, at least initially, forget about this or might even try to mask some insufficient skills by adding more layers. It may sound counterintuitive, but the more tracks you have in your production, the more quiet it will sound overall and the harder it will also be to mix.
So ask yourself: Why is this sound or part in the track? Is it necessary?
One way to quickly check if something is needed in the mix or not is to take the volume fader all the way down and slowly bring it back up. Or to temporarily mute the track. Does it make a positive difference or does it maybe even just clog up a certain frequency range? If you take it out, does your song seem to breathe or miss something all of a sudden?
Don't be afraid to let go of unnecessary things, even if that means you're effectively trashing hours of work. Even if you don't use what you spent a long time on crafting, it wasn't in vain. You practiced and honed your skills and the discarded bit might be perfect for something later.