What's the best way to master recorded vocals and instruments?

I’ve been playing and singing music for a long time – I’ve just recently started to dabble in recording. I know that everything needs its own “sonic space” so to speak – isolating different instruments and vocals so they don’t cover each other up. But I’m still having trouble with the specifics of mastering my recordings. Specifically isolating the bass guitar away from the vocals. I want both to be panned as close to 0 as possible, but the bass really muddies the vocals into a gloopy mess. I’m not an EQ master – at all – and anything I do to the vocals to get them away from the bass seems to make it sound like I’m singing through a telephone. I think I need a sound engineer!