My friend, cire113, my assumption is you are doing this, learning bass, for fun, maybe down the road to do gigs. Maybe you already do a gig here and there. In any case you want to improve, as most of us do.
The gentleman, Daemon said my advice is invalid. Maybe it is to some extent, but different advice is useful at different points in time- save my words, and maybe reread 'em from time to time.
Let's move on to some of the advice that btw is not just for you.
1."bass playing is about relaxed groove" what a misleading inappropriate time waster that is, eh, Damon?
Does anyone see my point here? guys who are just a tad "crazy" about getting better with their methods, sometimes get lost in the details and can't see certain angles of vision- such as number one thing - being relaxed while both performing and pursuing music. Hearing all manner of well meaning advice, from all manner of well meaning bassists, can be both confusing and might cause a lack of relaxation ... so I wanted to remind the up coming bass player about this. My apology for that, yeah right!
2. is About the absolute primacy of playing roots. It does not mean mindlessly so. You need to take SIMPLER tunes, with simple bass lines and nail them, period. No arguing about theory of roots vs less roots, just imitate the player who is playing on whatever tune. Take theory slowly, gently. Ask me a question about it if you wish.
Learn from other bass players and their bass notes- could not be simpler.
It is NOT hard IF you take my advice... keep it simple, and relaxed, and enjoyable. Music is about hearing and less about thought. Thought has its place, but too much causes tension. So "lower the bar a bit"... it worked for me!
I apologize to those of you, including Damon, and others, who think I am misguiding our fellow traveller- ha ha ha.
3. Is in two parts- Bass is about accompaniment. I just today listened to legendary bass player Bob Babbitt saying words to this effect. Sooooo sorry about offending anyone here on that score. second part is about the primacy of rhythm. Listen to Mr babbitt on youtube, wonderful guy and player who understands basses role. First learn the BASS role the BASIC role of bass, THEN delve into Victor Wooten Sheehan stuff.
So far we have RHYTHM, Accompaniment role, and primacy Roots also called FUNDAMENTALS ( I mean the freaking LANGUAGE even supports my too obvious statements !) , or the art of playing fundamentals.. aka roots and fifths, which is easy if you play easy songs, the way I did, in my untutored "sink or swim" "trial by fire", method. SOOooo sorry to Damon and other highly educated bass players, who know sooo much much about bass playing. I ought to schedule some lessons with some of you guys real soon, eh?
4. Repetition of a bass part. Another detail that I learned long ago.. Quick anecdote, I am playing a gig with a large sized blues singer and bandleader. he turns to me on stage and criticizes my note choices... too busy, or something or other. I later realized that his pov was valid. Simple is not mandatory, it partly depends on the style of music, but generally bass parts involves less melodic bass parts. Let's not argue, just learn from simple bass parts what to play. Repetition is a common part of many types of music, not all, but many. And simpler repetitious parts, are EASIER to play. They allow you to focus on SIMPLER DIATONIC TONES, GROOVE and being RELAXED. Which are the hallmarks of playing music.
I hope this is not too boring for some of you, you know who you are.
5. Is kind of superfluous, I admit, though still true.
6 Is a reference to endurance and a delineating factor between solo instruments and rhythm players, not necessary, but true.
7 Is a very advanced stage, something to look forward to, and by keeping it simple, with eg blues, country, rock- if you stay simple you will reach the ecstatic levels of the magical synergy of a whole band, much SOONER.
8 Just reiterates all of the above.
There is no way, that I am not going to let younger players know what I know, regardless of your opinions to the contrary.
I have played countless gigs, from concerts ( my first at age 21 with a top recording group ) to clubs with famous musicians in attendance. I have also played with many top musicians, though not at the present time so much.
I have seldom taught, and made my SOLE living playing music as a freelance musician since the sixties.
If my advice is inappropriate to some here, I am laughing at that opinion.
Good luck to you cire113 and others whose minds are still flexible.