Sweep picking is easy to nail cleanly, it just takes a lot of practice to synchronize your left and right hands together.
8 finger tapping is a lot harder, unless you can play ambidextrously, because it's teaching the right hand to do the same as the left, which the muscles haven't learned to do. The best way to really practice it is to start with basic hammer-on/pull-off exercises using each set of fingers on your right hand (1-2, 2-3, 3-4, 1-3, 2-4, 1-4). Once those are solid, practice some basic scale patterns using only your right hand; probably best to start with minor and major pentatonic, then move to 3-note-per-string scales. Just like how it takes your left hand a long time to get fast with the scales and legato work, it's the same with your right hand.
Another killer 8 finger tapper to check out is Bill Peck, instead of running wide arpeggios over the neck he harmonizes melody lines with both hands, and also taps some cool linear lines as well.