Harmonics are magic-sounding notes created in a slightly different way to a normal fretted note. Here's a very easy beginners lesson on how to play them.
Make sure you download the free The Bass Guitar Resource Book which contains (amongst a lot of other cool stuff!) a fretboard diagram of all the natural harmonics as well as some great chords to play.
Once you've developed the required touch and technique to play a natural harmonic, it's time to work out a few places on the neck that sound good. The Bass Guitar Resource Book has a bunch of chords that sound effective for solo bass, endings, and bass lines.
Here's a video with the chords.
You might then want to think about artificial and tapped harmonics. They're a step or two up, sure, but they sound awesome.
Make sure you listen to the masters playing harmonics. Jaco wrote the book on them...
Making music with various bass techniques is the goal. Once you know how scales and keys fit together, you can use harmonics with chords and scales and create your own tunes.
Here's a lesson on how to do that.