AGCurry said:
suggestions on how to process a Precision bass may not be appropriate at all for, say, a Rickenbacker or Les Paul bass.
. . . or a Jazz bass, for that matter.
You see, some basses tend to need a healthy boost in the midrange to get some extra growl out of them in order to cut through a busier rock mix. Precisions can sometimes fall in to that category. Others, like a Jazz or a Richenbacher, tend to have plenty of that to begin with, and may actually need some taming in the midrange in order to soften them a bit. Depending on the context of the mix, though, and how it's being played.
Another major factor is how old the strings are. Older strings have very little presence, while newer ones sometimes have too much. Where your right hand (assuming you're right-handed) plays in relation to the pickups actually has a very large effect on the tone, surprizingly enough.
This is a really obvious one, but it's worth a mention -- but the arrangement of the song and the bass part will have a large impact on how you'll approach EQ'ing the track. Namely, if the parts are in a higher octave, you'll probably find yourself cutting much less low-bass than if most of the parts are open, drop-tuned E string, for example.

Kind of an obvious one, there.
Whether you use your fingers or a pick will greatly affect how you will EQ the track (Sometimes you may need to cut some high mids if the the pick has too much attack, or boost if not enough). So many factors at play, but the genesis of a great bass track is to start with a great-sounding bass and someone who plays it the right way in relation to the song/arrangement. If you have those "bases" covered (no pun intended), you'll rarely need any EQ at all.