There is a widespread notion that great technique means one thing: that a bassist has great dexterity and facility and can play really fast all over the instrument. This is only one element of technique, and truthfully, probably not the most important. Technique is what we need to produce the sound or variety of sounds we want; technique gives us the freedom to translate our ideas to the instrument; with good technique we can learn the language developed by past and present masters, and develop our own unique voice on the bass.
One of the first things (if not the first) that we admire in a musician is his or her sound on their instrument. A great way to work on sound is through scales and arpeggios all over the bass. It is very important to practice these in an inspired way, and not to do so from an unconnected space. This is all about developing a deep connection to the instrument. So I DON’T encourage practicing while watching TV for instance. Find creative ways to practice scales and arpeggios so they are a musical experience and not just an exercise. This can be done in many different ways.
For example, practice a scale you play all the time with a different fingering. If you always have the same sequence of shifts to climb the G-string, change it up, so you shift on different notes. Or move up the fingerboard on the D-string instead.
You can also practice using different rhythms. For example, play two beats of quarter notes, two beats of eighth notes, then two of triplets, then sixteenths etc…

Mix up this sequence of rhythms liberally. It’s a great way to develop rhythmic flexibility. And one more thing about rhythm: everything you practice and play must be imbued with a deep sense of time. I advocate practicing with and without a metronome. Without, it is very important to have a strong inner sense of rhythm. Record yourself so you can listen critically to your time and rhythmic feel, and work on developing a really solid foundation. This is essential for playing all sorts of musical styles, and for communicating your ideas within a group or to an audience. It is also important in rhythmically freer situations, as it is my feeling that an underlying sense of pulse still remains in these contexts, albeit in a less obvious manner.
We all tend to practice our scales and arpeggios through the cycle of fifths, and this is a very good way to do it. It can also be fun to move them through different cycles. For instance, practice your major scales and arpeggios through a minor third cycle (C,A,F#,Eb etc…). A great way to work on achieving a uniform sound on the whole instrument is to practice from the lowest note available on the instrument in a given key to a high one. For example, I practice C major arpeggio from the low E to the G two octaves above the open G-string. You can also do them backwards; start in thumb position, go down, then go back up.

Scales and arpeggios are also a great vehicle for working on intonation. And, playing with great pitch on the bass may not be easy at first, but it is NECESSARY!!!! Don’t tolerate notes that are out of tune in your practicing. Practice slowly, both pizzicato and with the bow. Arco practice is very important. With the bow, there is no hiding from a note that is out of tune. A pizzicato note decays very quickly, but it holds through with the bow. So, even if you never intend to play a bowed melody or solo on a gig, some practice with the bow will strengthen your left hand, improve your intonation, and it will make your instrument vibrate tons. Your bass will love you for it. Slow bowing practice is also great for developing a relaxed way of playing the bass. In order to produce a big sound, you can’t force it or muscle it, you have to use weight. Your arms have to be really loose, and this holds true for making a big sound plucking as well. Over the years, this sort of work has helped me out enormously.
Good sound, solid time and rhythm, and great pitch are crucial for any bassist. These components are at the heart of the bass’ function as part of the rhythm section and they will allow you to contribute in an inspiring way to any ensemble in which you play.