Another classic battle in the mixing process is the kick drum vs. bass guitar. That is because they share similar range of frequencies. While in some cases the bass plays more important role than the kick, more often they are expected to be of same importance.

• try assigning different low-end frequencies to each instrument. For example, you could boost 60Hz on the kick drum, while boosting 100Hz on the bass. Or vice versa. This allows them to fill up the bottom spectrum end without competing with each other.
• Usually you want to see the kick and bass as well as feel them. That is, you wish to hear the actual notes of the bass and the rhythm the kick drum plays. Finding the right midrange frequencies to feature is the solution. On the kick, try adding around 2K for presence and 10K to put a "light" on it. For the bass, it might be 5K or 8K that allows the instrument to pop up in your mix. You can also try with 800Hz for an aggressive bass sound.