I've lived here almost 27 years, so I guess I can chime in on this.
First, I would quibble with the idea that playing ability is "secondary." It's absolutely true that if you're a jerk, or people sense that you're so overtly ambitious that you can't have a normal conversation, then playing great won't save you. BUT... this town is full of really, REALLY good players. It's pick it - or pack it. In nearly three decades here, I've seen countless hot-shots come to town from the coasts (or elsewhere), desiring the easier, laid-back life, a better place to raise kids, etc. Some arrive thinking it's all C chords and hay bales, and assume they'll walk in and show the hicks how it's really done. Almost always, they're stunned when they see how efficiently creative things are here, and how many killer players are vying for the work. Can't count the times I've seen this type get his butt kicked. This may be the only town in the world where your pizza delivery guy can very likely play you under the table.
That said, it's not about being Victor Wooten (no offense, Victor!). A bass player will find a place here if he/she can listen, groove, get tones that fit and inspire the other players, play lots of styles, adapt, work with people, be inventive, and most of all... SERVE THE SONG. It's not about how much stuff you can play. It's about making the song - and the singer - sound good.
I've toured and recorded here as a guitarist, bassist and trumpet player, and I can tell you that there is world-class rock, pop, R&B, Contemporary Christian (P&W!) and country recorded and played live here every day. Versatility is not merely appreciated; like all the foundational elements that make up a good (GOOD) player, it's required. And all that - what, to me, makes up a ready-for-prime-time player, isn't secondary. It's just assumed. Don't come here if both barrels aren't loaded as described above. Or if you do come, I hope you know your way around a pizza route.
Secondly, the attitude thing alluded to in previous posts, the getting along, the hang... That IS really important. Players want to be around people who are nice to be around. Sessions are usually (or should be) full of good humor, interlaced in the serious business of gettin' it done. It makes the workday go a lot better. And if you need to stick out, if you bring a negative "thang" to the process, if you're all about you instead of all about the song and making it better for everyone, they will look over your shoulder at the long line of good players behind you, waiting to load in, and ask one of them to come in and sit down.
I'm not sure I know anyone here who didn't play some free stuff while getting established. And you will see people whose names you recognize playing freebies quite often - if the music is good. You're a musician. You play. Sometimes the music, or the hang, or doing a favor for a friend makes it worth playing for no pay. And when you're starting out here, it's often the only way you'll get to plug in and play for a while.
The plumb work here is in sessions (you'll start with demos, and maybe move up to masters, which are records) and, to a lesser degree, touring. The usual path (if it's working for you) is that you find some scruffy live gigs, and meet some people that way. Then one of those new friends brings your name up for a few road dates. Mid-level stuff... maybe an older artist who's not on the charts anymore, or a noob who's got label interest, or maybe just a regular old club gig in Resume Speed, Iowa. It's work.
Then maybe you snag a good artist gig, and tour for a while. "Touring" here is not typically a matter of being out for months. You leave on, say, a Wednesday. Play three shows in different towns. And you're back Sunday night. In the Summer, with fair dates and lots more concerts, you might be out for a few two and three-week stretches.
At any rate, for many touring players, the eventual goal is to get enough session work going - or a writing deal, or maybe some production projects - that you can stay in town. I cannot count the people I know who have followed (or tried to follow) this basic path.
At every step along the way, your work will come from other players. The drummer you did the freebie with. His bud, the bass player who happened in on that freebie gig. Etc., etc., all the way up to the master session stuff. You don't "apply" for gigs. The bass player's leaving. The drummer and guitar player mention this bass player they did a free thing with last week... good groove, nice cat, really great tone. He's in. If you were the guy who got up off his butt, left the season premiere of "CSI Wherever," and went to play that little freebie, well...
There is some paying club work on Lower Broadway. You might make $80 bucks for a four-hour gig. Maybe more - some of the better bands (those who know how to entertain & pack the place - AND work the tip jar) make a couple hundred a man. But it's tip-jar based. The clubs on Lower Broad make money hand-over-fist, and they have a pretty steady system. Most guarantee $50 a night per man against tips. If you stink, or if the band playing next door that night has a fiddle player who looks like a centerfold (it happens), you might be taking home the fifty. A few clubs in other areas pay a little, but not many, and not much. People play them to showcase, or to keep playing, or to get a band together. Back in '84, when I came here, I left a very steady world of club & society work. My wife didn't have to have a job, and we did fine. The first night I worked in Nashville, I was thrilled because the singer/writer had two songs on the current Alabama album, two members of the Nitty Gritty Dirt Band sat in, and I'd read a piece on the other guitar player in Guitar Player Magazine. Wow! I've made it already! That night, my take from the tip jar was $6. Six. Dollars. Ouch. But the drummer on the gig called me for another, and another. I worked a bunch with him for a while. A few years later, he formed the band Restless Heart. That's how it goes.
Another thing to get together is tunes. Silly as it sounds, know everything. You're not going to rehearse for a Lower Broad gig. You get a call, and you show up, and you make it sound like you've all been playing together since birth, even if you're subbing and you just met the guys for the first time while you were tuning up. I try to think of it this way - if I hear a classic rock or country or pop tune, I need to know it. Period. Of course you can't do that entirely, but you should try, cause looking in the eyes of a guitar player who just called the ONE dang Tom Petty tune you're not hip to is a lonely place to be.
You won't rehearse for sessions, either, except in some cases on REAL big projects, and by that time you'll know all this. You show up, sit around with the writer playing a guitar or work tape, make your own number chart (on bigger stuff, the leader often makes charts ahead of time), and go in and cut the song that you've just heard for the first time. Many, many, many of the records you've heard were cut that way. A run-through for arrangement, another to settle the parts, and it's red-light time. On a typical three-hour session, the goal is often to get five songs. And they'll sound like masters. Cutting fast while maintaining quality is a skill, or a bunch of skills that work together. After each keeper, you go into the control room or lounge, listen to the next song, make your chart, and do it again. It's a lot of pressure at first, but you get used to it, and it's fun. And this is a lot of where the being a nice guy thing comes in. That diffuses the pressure of the situation.
Lastly, number charts. Learn how that works. It's not rocket surgery, but it'll help to spend some time working that way before you get here. Know enough about theory that you REALLY know your keys. If you don't INSTANTLY know the 6 of Bb, you will NOT hit that G root with the drummer. Do that a few times, and they can't afford to call you again. Number charts make it possible to play a song right now, in any key, with any groove, and nail it. Learn to write and read number charts.
I hope all that is helpful or at least interesting to some. This is a great town. I wouldn't live anywhere else. You can form lasting, great friendships, raise a family humanely, live creatively, make a (somewhat) decent living most of the time, and always have the potential to hit a home run (big session career, songwriting success, whatever). Sometimes it seems like there are two million good bass players in town. But a nice guy who can play, and can leave the ego at the door, has a pretty good chance of keeping the bills paid. I should temper that by saying that, right now, things are as lean as I've ever seen them in Nashville. The record business has fallen apart, and nobody's really sure how it's all going to shake out. Even the vaunted "A-Team" session players are doing demos and a few tour dates these days. Just sayin'...
Rusty Russell
, my gear is ready to go, and I just got a room in someones trailer outside of Nashville. I'm ready to start gigging everything and anything. However, I don't know a soul. What would you say to do? 
