Another example how to come up with a bass line and how to spice it up a little. http://johannes-oehl.jimdo.com/bassu...p-bass-lernen/
The chord progression is a fairly simple: I-IV-V minor (Em7 / Em7 / Am7 / Bm7)
The first idea is to use just the root and octave. The root is played on the "1" and the higher octave is placed on the "2+" which adds a syncopated feel to the rhythm. The other notes are on "3+", "4" and "4+". Notice that the bass never playes along with the snare (played on "2" and "4"), which creates a laid back and relaxed groove.
-> Em7 Am7 Hm7 Slap Bass 1.pdf
To make things a little more interesting, I added some 16th notes but kept the basic feeling. In the first two bars I used the minor third, minor 7th and perfect 5th. In the third bar I created the sound of Am7 9 13, which is a little more colorful.
->Em7 Am7 Hm7 Slap Bass 2.pdf