I recently quit lessons. I've been playing bass for 2 years and I've been going to lessons for a year and a half. Right now I'm in a jam band where we need alot of improvisation skills. One of our guitarists is very good at improvising(has been playing for about 4-5 years) and so is the other one even though he has only been playing guitar for a year. The thing is, i need to learn how to improvise on my bass guitar as soon as possible. I feel like I'm the weakest link in the band. I can't improvise that well in these simple mixolydian aeolian... w/e scales. I haven't even memorized most of them yet. I only know aeolian, blues, lydian, myxolidian, and major/minor penatonic scale. These scales sort of sound bland in the certain keys we play in. Sometimes i hit the "wrong" note when these stupid scales are supposed to be so called "fool-proof". My question is, how can I improve on bass without an actual teacher(The cost is outweighing the marginal benefit)? What should I practice everything and for how long(i need a set schedule)? How can i improve on improvisation?