I am an experienced bass player. I mainly play bass for my songwriting as a solo instrument. I am singing over my lines. So I dont play for other bands. I can slap, tap, play some funk. But I always seem to play at the same level. I got many books like Mark King Bass Lines, Bass Hand Exercices etc... I care more about performance rather than theory. But I dont know exactly where to Re-start practicing and how to learn great new riffs in a step by step fashion. Any general advices on how to have a progressive study plan?