Originally Posted by pfox14
Sounds like you could benefit from taking some lessons. Try and find a good bass teacher to help you improve your technique and practicing regimen.
+1 on lessons.
What are some songs you have heard that you liked the bass lines in? "Jazz" covers a lot of styles, your idea of a jazz tune may not match mine.
Keep in mind that bass lines in improvised jazz are not written parts, the note choices originate with the player's musical knowledge - scales, chords, etc. - that he fits into the group in real-time.
A good way to start developing this skill is to play some blues. Start with basic 1-4-5 progressions, detailed knowledge of music theory not required.
Good luck and have fun.