From what it sounds like, you should already know how to read music. Remember that the bass guitar, while it reads bass clef just like tuba and baritone b.c., sounds up one octave from where it is written. (This is mainly so composers wouldn’t have to write so many leger lines below the staff when composing for bass – upright bass or bass guitar.) So the lowest written note for the bass guitar is an “E” on the first leger line below the staff, yet it sounds the pedal “E” one octave below that!

The next thing you need to think of are the styles of music you want to play on the bass. If you are just interested in playing your favorite rock tunes, you can go out and find a method book that will teach you the fundamentals of bass technique in rock. The same applies to other styles of music as well.

Third, think about your low brass playing techniques. We have exercises for all aspects of low brass, don’t we? Long tones for breath control and steadiness of sound. Articulation for consistent attacks for each note. Lip slurs for agility between lip positions. And scales for note patterns and music theory.

Apply all of that to the bass. You need to practice your right hand attacks on the the strings so they are consistent. You need to work the left hand so that the notes sound and sustain properly. You need to coordinate between the hands so that attack and note sound as one. You also need to practice your agility between strings, with both hands mind you. And lastly, you need to know your scales on the bass (major, minor, modes, pentatonic, etc.) so you understand how the note patterns go.

I haven’t had a chance to do this myself, but I would also recommend some lessons. One day soon, I plan on doing exactly this, because a teacher should know the answers to questions I have, or at the very least, will know where to look for the answers.

Anyway, good luck.
VT

Bass guitar is a lot of fun. =D
Good luck!