Basslines that connect
Roots explain the harmony; rhythm and approach notes turn the explanation into a line.
Bass has two jobs at once: it makes the low-frequency foundation and tells the listener where the harmony is. Start with roots; earn every extra note.
Listen for: The root makes every chord explicit.
Roots make the map readable
The root is the note a chord is named after. Playing it when the chord changes makes the progression obvious. Repeating roots is not boring when their rhythm locks with the kick.
For safe movement, try the octave or fifth. An approach note sits one step above or below the next important note and creates a tiny pull into it. It works because the destination arrives immediately after.
Share the low end
Kick and bass occupy the same scarce region. Let one speak in the gap of the other, or make one short while the other sustains. A complicated bass rhythm becomes clearer when the drum part leaves it a door.