I use Pro-tools plug-ins for compression......As far as vocals you've got to feel that one out. I layer my hip hop vocals, sometimes twice, sometime with just ad libs, and use reverb. Just a touch, not so much that it has an ols school sound to it. You can't hear it when the track plays behind it, but it helps the vocals blend in with the track......As far as instuments, I route them to an aux track and add compression to that, rather than doing each one separately.