2. Understand that when divided in half, a string produces the same note, but an octave higher.
3. Understand that there are only 12 possible tones on a bass guitar. They repeat in lower and higher registers, but a C is a C whether low or high.
4. Link tip 2 and tip 3 together: The octave is subdivided into 12 steps. Each is represented on the bass guitar by a fret. If you keep counting after 12, 13 will be the same as 1, but an octave higher.
5. Understand the "distance" between the strings (the fancy word is intervallic relationship. Each pair of adjacent strings is separated by a perfect fourth. If you have problems understanding intervals, go back to that, and come back when you are ready.
6. Learn how a major scale is played on any single string. For now it does not matter if it sounds good. Just focus on where the notes are ON A SINGLE STRING.
7. Say the names of the notes out loud as you play the major scales we've just discussed.
8. Sing everything you play on bass. This will engage your sense of hearing at a far deeper level. It will help you grasp the bass fretboard from your intuition.
9. Visualize all of what you have learnt in your mind's eye. Form a clear mental picture of it, and picture yourself going over all the steps. Practice this for 5 minutes a day, until the image is clear and sharp.
10. Download the free fretboard diagram here, print it out and tape it to your music stand, and put one in your bass case! Try to spot relationships as you go along. But don't worry too much about it. Your understanding of the bass fretboard will deepen together with your understanding of theory. Take it one step a a time!