double bass IMHO is what makes drum solos and such sound good and full.. therefore I think it's def a skill thats worthy of getting and working hard at..

i suggest not moving your leg up, practice heel down.. a lot of double bass is ankles, calves, feet, and toes

try to keep a steady beat and increase speed as you go along.. make sure the notes are even

don't you just love the burning sensations in your legs you get ?? haha at least you know you're getting faster every second