First off all; I read on guitar-world.com a lesson from Kirk Hammett (metallica lead guitarist) that he uses his middle finger to pick the string with on to the fretboard(and not the pick) I started using this technique, and it was MUCH better. After getting used to it u have much more control.

The right finger on your left hand should be your fourth finger (or pinki finger? bad english...) If u are going to pick like this: (t=tap)
|----19(t)15p12----19(t)15p12-|

Using the right finger on right fret makes playing a lot easier! :)