Watch the Blues Forever: Melody online guitar lesson by John Goldsby from Upright Bass Handbook
Now let's play the "Blues Forever" melody at a slightly faster tempo. Repeat the 12-bar blues once. I use my right hand index finger to pluck all of the notes. You should also be able to play everything with your index finger, but you can also experiment with using two-finger technique on some of the phrases. When playing an "8th note line" in a jazz swing feel, play the 8th notes with a slight triplet feeling. That means the 8th notes dance with a rhythmic feeling similar to the drummer's ride cymbal. Listen to bass players like Jimmie Blanton, Oscar Pettiford, Ray Brown, Paul Chambers, Percy Heath, Sam Jones, Charles Mingus, Red Mitchell and Scott LaFaro for an insight into jazz bass solo phrasing.
You can add a lot of inflection to this melody. Make sure you have the fingerings correct, but once you can play the notes, try and sing the line through your instrument. Notice that I've marked accents over certain notes, like the 4+and in bar 1, and the 2+and in bar 2. These are important inflections to give the line a musical shape.
Bars 1 and 2 of this melody are based on a Bb blues scale. Bars 3 and 4 use a mix of chord and scale tones. Bars 5-8 repeat the melody from the first four bars. In bar 9, we find a C minor 7th arpeggio, starting on the b7--the note Bb--and moving down the arpeggio. This is a different concept from the basslines where you've been starting on the root in every bar. Here, you're playing like a horn player: starting at the top of the chord and playing down the arpeggio. Finally, bars 11 and 12 use a variation of the opening theme.
Also note that I often slide into the note Db to add some inflection and blues sound to the melody. It's important to play all notes with good intonation, but the upright bass lends itself to sliding and left-hand inflections when the music calls for some extra "stank"!