A good bass mix, or any mix for that matter, starts with good sounds going into the mix. You can't imagine an engineer's frustration when a bass player is trying to achieve a sound during the mix process that just isn't on the tape. Take the time to sculpt your bass sound the way you want it before you even hit record. This will make the mix process much easier. If the bass lines to a tune are very busy, cutting away some of the "boom" in the low end will add the clarity you probably will want to hear. If the bass is laying out long, low tones, you may want to leave in that low end to make the track sound nice and full.
One factor that's often overlooked by novice engineers is where the bass guitar and kick drum are sitting in the mix, in regard to each other. These instruments generally hover between 40 hertz to 200 hertz. The bass and kick need to share that space, so you might want to remove a frequency from the bass, if that is where the "sweet spot" of the kick drum is. For example, if the kick drum's spikes are really prominent around 150 hertz, try cutting that frequency out of your bass guitar. This will prevent the low end from sounding muddy, and will allow both instruments to cut through in the mix. It takes some time to master this, but giving the bass some space to breathe is essential to making a professional-sounding record.
With all the EQing (equalizing) you may wind up doing to the bass, you definitely should consider some kind of compression on your bass sound. The goal here is not to totally squash your sound, but rather smooth it out and make it more consistent. You may notice on playback that the bass is very resonant on certain notes and then seems to disappear on others. This can be caused by a combination of factors but provided that the other aspects of the mix are where you want them, a little bass compression will solve this. Unfortunately, there is no formula for figuring out just how compressed the sound should be. A good engineer needs to use their ears. Play with threshold and compression ratios until the bass sound comes through consistently during playback.