Hi,
I would second all the points about practicing scales etc, both across and along the strings, in all positions and all keys.
Yes in the beginning it is can be boring, I still practice them but make them musical!
The point about using a keyboard is good, I play through a difficult passage on the keyboard to hear what it sounds like, then practice it on the bass.
But I am not sure about using dots....
The main thing is that you know that you are playing out of tune, which is a step in the right direction!!!