Less is always more.

What I mean by this is that you should start by cutting frequencies instead of adding them.  For whatever reason, the general consensus (and my personal experience) is that plugin equalizers do a good job of cutting frequencies, but not so much of adding them.

Make some room.

I highly suggest that you start by cutting low end out of instruments whose key frequencies are not found on the super low end; this will make room for your bass and kick.  Often, this will translate into a clearer high end once you get into mastering.  A messy low end can affect compressors and limiters in odd ways, and I have found many mixes whose high end because a mess because of a mess at the low end that a limiter couldn’t handle.

Just take a listen at the difference that a low cut filter makes on drums and hi hats…