The bass and drums form the song's feel or groove. If they're mixed correctly, you're already half way home to a great mix. Start with the kick drum. Adjust your mix monitor level to where you normally like to listen. I like to work with VU, not peak meters.
Peak meters are for wussies.
Add a little 2.5 K for attack if you need to. Roll off a little 300HZ if the kick is a little tubby in the lower mids. Bring up the bass guitar fader until the bass becomes a cohesive unit with the kick, and the two of them seem to hit you in the chest. Now add the snare to the mix. Bring it up to a level that rivals, but doesn't exceed the level of the kick and bass.