well, go to youtube and watch victor wooten doing his little instructional video on how he does his technique, and then you'll decide to give up on playing!
seriously though, it sounds like you need to build finger strength. there are numerous things you can do such as those little finger strengthening spring deals, or a squeezy toy. keep one around and just pick it up when your hands are idle and give 'em a workout, both hands!
also, lay your hand flat on the table and try lifting each finger independently. keep practicing that. do patterns, repititions, variations of that.
personally i've been practicing using three fingers. i've used two for a long time and i'm pretty quick at it, grew up on upright bass, but i love the whole triplets ability with three fingers and the ability to let one finger rest... so you start slow doing quarter notes. just go 1-2-3-2 or 3-2-1-2 or even do 1-2-3-1-2-3 3-2-1-3-2-1 and make variations on those patterns (which finger to pluck with) and start slow, and slowly build up speed. don't be afraid to use a metronome (in fact i encourage it) or a drum click track.
anyone else have other techniques?