Do you mean the vocals end up masking everything else? Or do you find yourself making a bunch of adjustments to the instruments to help the vocals sit better, and therefore lose your mix you had with the instruments?
I don't really run into this problem, probably because I treat the vocals almost as an afterthought, haha. I try to get all the instruments slamming as best I can, with the vocals muted, and if the vocals don't sit right as soon as I drop them in, I adjust them to fit the mix I already have, as opposed to making holes in my mix for them to sit inside. My kick, bass and rhythm guitars take priority for me, and everything else conforms to them. Probably the wrong approach, but fuck it. I'm a hobbyist, so do what I want. I have unprotected sex and I kill people.