If you want to improve any aspect of your bass guitar technique, try following the steps in this week's video lesson.
Scroll down for the two octave G Natural Minor shape I used in the lesson.
How To Improve Your Bass Technique In 5 Simple Steps
1. What bass techniques do you really need?
Decide what kind of bass player you are or want to be. Then you can focus in on the techniques you really need (and ignore those you don't!).
2. Figure out the mechanics of the technique(s)
Work very slowly on what your hands and fingers need to do.
3. Work on your speed (ECONOMY OF MOTION)
Build up your speed from the solid foundation you built when working on mechanics.
4. Work on your timing
Good technique without great time feel is not worth much.
At this point, use a metronome or drum loop to develop your groove and learn to play bang in time.
5. Sort your practice routine out
Consistency and a regular practice routine is key! Without this, you won't truly reach your full potential.
And here's a lesson to help with your practice:
Here's the two octave G Natural Minor shape I used in the lesson.

Bass Guitar Resources
Complete Fingerstyle Bass Technique. This will teach you about all the basic techniques you need. Basically, everything apart from slap and plectrum.
Creative Bass Technique Exercises: 70 Melodic Exercises to Develop Great Feel & Technique on Bass Guitar