Welcome (tho, as much as I love the bass and acknowledge that I AM a bassist, surely I can't be the only one of us who occasionally thinks wistfully that I might have fallen in love w/ a more portable instrument!

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When I wanted to join a rock band in college, my roommate gave me a couple of lessons on bass guitar. His first lesson was to teach me the G major scale, his second lesson was to show me how to play 1/4/5 in that scale, and his third lesson was how to play the major scale pattern on the 4 and the 5. He then told me that principal transferred to songs in any key. Some 40 years later, I can still remember him telling me that I was now ready to play something like 90% of all rock and blues songs.
Now that I'm playing mostly BG/oldtime/Americana, what cracks me up is how often I'll be playing with someone who is quite accomplished at their instrument, and after all their years of experience, they'll comment on their brilliant breakthrough/discovery - of something encapsulated in those 1st 3 lessons I described above!
Now that I'm trying to develop skills OTHER than simply being solid, I'm working on learning to read bass clef, improving at various scales, and figuring out the fingerboard above 1st and 2d positions. But I frequently think how fortunate I was to have my roommate boil things down so effectively when I began.
Sometimes I kinda regret, tho, when I KNOW where the "correct" note is on my fingerboard, but I'll have to stop and think about it before I can name that note. And then I have to think even harder to figure out the theory as to why that is the correct note.
Keeping a steady tempo is your number one job. That's true for bass players in every genre, but especially when there's no drummer.
I agree that a steady tempo is likely job #1. It is often said that it is more important for the bass to play A note at the right time, rather than the right note at the wrong time.
And altho there is no drummer, there IS (optimally) a mando. Or at least a solid guitarist whose boom-chuck you can lock in with. Work on distinguishing the 1-3 beats, from the 2-4s. And (one of my pet peeves) - play ASSERTIVELY! I HATE it when I encounter a jam where the bassist is playing tentatively.