I played bass in a rock band some years back and did an okay job. But cannot do jamband nor do I do play bass anymore.
I spent alot of time working on country songs (did alot of Johnny Cash) and Motown and Stax. One could say: Sun, Motown & Stax
That taught me the basics:
1. Sync with the drummer and ensure the drummer never hits the kick without hitting a note
2. Know the chords, the changes, the key of the song, when to play in the scale of the song's key and when to play in the scale of the chord
3. 99% of the time when there is a chord change be on the tonic
4. The V is called dominant for a reason
5. The vii is called leading for a reason