To go along with Deon, I think it is important to have a mix that sounds good before you use any compression. That will not save a mix and should only be a slight enhancement.
Back to the topic of arrangement, I don't know if I started saying this back in my studio session days, or if I picked it up from someone, but either way, it is true that if the rhythm section doesn't feel good, the record can't be saved.
Based on the genres you list, you may not have a lot of instruments besides the rhythm section' but it is true that a good feel with bass, guitar, and drums (and any basic keyboard backing part) is crucial. I use acoustic guitar on 90% of my songs, and I spend a long time just listening to guitar bass and drums.
I know this is getting a little bit off the original question, but just thought it might help. Maybe someone reading this thread is focusing attention on the wrong things.
I start mixing with the kick and bass guitar, then add in the other drums and the rhythm guitar. And I may mute any one of those three at times to see how it feels. From there I add vocals for a rough level. Then I take vocals out for a while while I build up the rest of the track.
Probably not the only or even best way to do it, but that's my drill.
Regarding gain-stagin (and this will get us way off topic), I try to keep each stage in range for mix flexibility, but in the digital realm, I'm not sure how much that alters sound once you're in the box.