#1
I've looked around on this site, and I can't find anything about coming up with your own bass lines, which i want to try. Does anyone have any advice on how to do it or where some lessons for it might be.
#3
Just fiddle around, and when you find something that sounds good, write it down. Thats how it works for me.

Learning scales definitely helps a lot.
#4
Find out in what key the song is, use that scale.
'Have you felt the trembling in your stomach, the bass that leads us there'