Well, as for "tips", I would respectfully suggest that rather than worry about popping and slapping and all that gimmicky stuff, spend your time taking your favorite band or bass player and learning their techniques. Lee of Rush comes to mind - although I would put him in the category for a "beginner"
Check out older players such as "Duck" Dunn, James Jamerson, Carl Radle and the like. These guys all had EXTREMELY productive careers playing SOUND fundamentals. Holding and keeping a groove. Theory. That sort of thing.
Once you have the basics down (not that you don't), then venture into some of these "younger" bass heroes and learn how to slap and pop like a crazy guy.
THEN, when you are comfortable, get with a band in your area that is looking for a bass player! Best way in the world to learn the gammit.........
Good Luck to you!
*edit* just caught the post - I "WOULDN'T" put him in the beginner category......my bad!
RF