I've been playing guitar for a few years and since I don't have a band I figured this might be a good way to go. Now I live in Tampa FL...which is not a hot bed for recording studios but it still has a few places. My question to any session players is, how did you get started? What were the sessions like? what did you play and where did you play? How demanding was the overall atmosphere? things like that.
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Tutorial: Studio Quality Programmed Drum Sounds
You just need tonnes of experience , most session players start by playing with as many bands and solo artists as possible until they are known by the producers and people at studios. The atmosphere though is you have to be ready to play at all times, they will call you in and youll play on a track after reading the sheet music for 5 minutes or so etc
I did it for a year and it was not my cup-o-tea. Lots of time pressure and deadlines. No live audience to feed off of. We did in-house video soundtracks, jingles and a few TV spots that played in greater LA markets.

You need to know people in the biz and they have to like you and like your work. Just showing up outside the studio with a guitar in your trunk probably won't work.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
yeah most session players are veterans of the scene. Just join bands , play for solo artists , just be everywhere and do everything.
You need ALOT of experience. Basically you have to be completely confident and in control of your instrument. When an artist asks for something, you deliver what they want. It is not very satisfying musically. It's basically what pays the bills though.

However, i will say, that if you are bored because you have no band, nothing will kill your joy of playing music faster than just being a dancing monkey for one bloated ego or another. It's fun in the beginning, but it gets old really fast.