I forgot to mention a couple of things that are more related to the playing/recording aspect:
While it may sound silly, but playing "noisily" can really help you get your bass to be heard. What I mean by this is to not be afraid of some "clickity clack" percussiveness when playing, especially for heavy, accentted notes and hits. The frequencies associated with the percussiveness of playing bass are in the high mids and highs, and they really help the instrument cut through. Of course this all depends on the kind of music you're playing and the sound you want. In my band, we all play fairly busy parts, and being a bass player who's heavily inspired by Geddy Lee (Rush)'s playing, I really want my instrument and lines to be heard rather than be an extension of the guitar (at least most of the time). Playing fairly aggressively helps me get a good attack and definition in the mix. For softer stuff, I'll try to get a rounder tone by plucking by the neck with the meat of my fingers (this helps to get the "bass as an extension of the guitar" sound).
Again, this may sound silly, but it really works. I remember reading an article somewhere that mentioned how someone, I think it was the bass player for Steely Dan (?), who had a lot of noise when he recorded. The producer or enginer made a comment along the lines of his playing sounding like he was working on a Cadillac or something, but in the end it helped give his playing life on the recording, rather than just sit back and get buried in the mix.
Also, the comment about strings and where you play on the bass are key. Along with these is getting a good bass tone to begin with. Sure, you can, and will, mess around with the EQ after it's recorded, but that process can't compare to getting the sound you want from your amp/bass and then recording that. I personally go for a very midrange sound (both when playing and recording), as that gives you the best definition along with power. Of course this depends on how you play, i.e. fingerstyle vs. slap. If you're slapping, you need lows/low mids and highs. Mids are usually heavily scooped in the traditional slap sound (eg. listen to Marcus Miller). But if you're playing/recording fingerstyle, which is what I do pretty much exclusively, my experiences with EQing might be able to help you.
The low mids and high mids give me the growl and punch that I need, so I try to boost those some while cutting the rest a little bit. Low-lows will be almost worthless when it comes to recording, because most of those frequencies will conflict with the kick, plus they'll probably be filtered out via a HPF. This where the low mids let you get power and definition. The mid-mids can give you a nasal/honkey sound. This is really a matter of taste. I personally am not really a fan of this kind of sound, so I'll usually leave them as is (i.e. flat) or maybe boost them a bit so that if need be, I can cut them once recorded. High mids help bring out percussiveness and add definition. The highs as a whole I'll cut and/or compress. Once most of the other instruments are added in the mix, the highs from the bass track will be buried, so they're not exactly very significant.
Some may disagree with me on this one, but I think it's tough to get "too much midrange" when recording. Sure, too much can produce an infavorable tone, but the good thing is that you can always cut in the editting stage if needed, which is always better than boosting.
Anyway, hope these tips help.
