Pull-offs

Hey all,

I've somewhat recently made a more categorized routine for my practice schedule where I work on specific techniques or chords or something each day.  One of the things I practice is hammer-ons and pull-offs.  Hammer-ons I've become quite good at, but I'm still not satisfied with my pull-offs.  My routine goes as follows (for those interested in adding something to their own practice):

Pull-off with 1st and 2nd fingers on each string, high e to low E and back again
Pull-off with 1st and 3rd fingers on each string, high e to low E and back again
Pull-off with 1st and 4th fingers on each string, high e to low E and back again
Pull-off with 2nd and 3rd fingers on each string, high e to low E and back again
Pull-off with 2nd and 4th fingers on each string, high e to low E and back again
Pull-off with 3rd and 4th fingers on each string, high e to low E and back again
Pull-off with 1st, 2nd and 3rd fingers on each string, high e to low E and back again
Pull-off with 1st, 2nd and 4th fingers on each string, high e to low E and back again
Pull-off with 1st, 3rd and 4th fingers on each string, high e to low E and back again
Pull-off with 2nd, 3rd and 4th fingers on each string, high e to low E and back again
Pull-off with 1st, 2nd, 3rd and 4th fingers on each string, high e to low E and back again

I do the same pattern with hammer-ons.  Anyway, here's my actual question.  Can anyone tell me what you're actually supposed to do with your fingers when you pull-off?  I've seen suggestions to just pull straight off of the string very quickly and I've seen others say that you should kind of pluck the string or 'flick-off'.  I've had some successes and some failures with both techniques.  With pulling straight off, I often don't get a very clear second note (it's very soft).  With the flick-offs, it will often sound like I'm just plucking the string, which ruins the pull-off.  Any advice would be greatly appreciated!