Watch the Lower Leading Tones online guitar lesson by John Goldsby from Upright Bass Handbook
Focus on the target note on beat 1 of each bar. Whether you play one, two, or three half steps leading into the root, the goal is to always outline the root movement. You might notice that sometimes a leading tone does not belong to the sound of a particular chord (for example, on a Cmin7 chord, using the note E to lead into the root F in the next bar). Basslines, like all good melodies, use tension and release, and sometimes there is a clash as the notes in your bassline move chromatically into a new chord. This is normal, and adds to the "forward motion" of the line. In this exercise, focus on shifting in and out of the first and half positions precisely.
If you find that the playalong track is moving too fast for you, stop and play the line out of time, making sure you know where all the notes are, and where the shifts occur.