Ultimate Rhoads

I'm trying to get my speed up to a good speed on bass. Think like Stvee Harris Ace High outro kinda speed. Thing is, it sounds crap and it's really annoying me.

Problem 1: the notes are horrible. They're really short and really quiet. Any way you can think of to help me get them the right "strength"?

Problem 2: vibration from other strings. When I switch strings, the others are still vibrating ever so slightly. This is alright in songs because it sorta fits in with the vibrations from other instruments and isn't noticeable, but I stil wanna get rid of it.

any tips?

put your picking hand's palm to mute the string that vibrates to stop it ringing quickly while switching strings or just let it ring, i guess. try different things