Artificial Harmonics are a good way to get your playing into a higher register. With this method, any note on your bass can be played an octave higher.
Basically, to play an artificial harmonic (I will use Bb flat as an example) press the note as if you were just going to play it normally (3rd fret on the G string) with your left hand. Then, with your right hand, place your thumb one octave higher, in this case it is the 15th fret, and just rest your thumb as if playing a harmonic on the note. Finally, with your right middle finger, pick the note behind your thumb (nearer the bridge than the neck.) If you did it right then you will have made a harmonic.
Try this a few times, then walk up the bass's neck one fret at a time and do the same for each note. Stop at the 9th fret.
(This is shown below).
Practice until you can play this up to speed.
