The first thing you need to do is really listen to your mix and try to get a clear picture in your mind of what needs to be done. Once you can really hear what you'd like to fix, then you'll know whether you're going to want to EQ and how you're going to do it....or at least you'll be able to come up with a specific question.
I'm not being rude, it's just that whether people EQ and entire mix or a single track or a group of tracks...it's totally arbitrary. The answer is usually yes to every question like this! Listen first and worry about technique later.
Slackmaster 2000