I have been trying to learn one hand tapping on guitar for a while now but am having some trouble. Lately I have just been tapping out a E major or A major barre chord shape slowly and trying to get coordination at this. I keep having trouble with my pinky finger striking against other fingers when I am holding down other fingers to make the sound ring out. My aim is to eventually play simple fingerstyleish songs with this technique. Is there any way that I can practice in a more efficient way? Any exercises? How can I learn to hit the frets harder to make a louder sound with weak fingers? Is there a trick to not hitting one finger with another? Is this even a widely used style?
I'm guessing you're talking about hammering on. Where the fretting hand fingers tap the strings onto the fretboard.
You need to use a hammer action - hence the title - where the fingertip hits down suddenly on the string,as close to the fretwire as possible, and keeps pressure on for as long as necessary. Start with something like 5th fret, top string, and hammer on with the index finger. From about an inch above the fretboard. Do this 10 times or so, at about one a second. Then move to fret 6, and middle finger, same process. Then 7, with ring finger, keeping the pinky out of the way, which should happen naturally, as it's shorter. Then fret 8 with pinky. If that proves difficult, it's no surprise, as the two fingers are almost Siamese twins! There's nothing wrong with snapping ring and pinky down together, it may help.
When that's good, go to next string, and so on, until you get to the fattest, also the hardest. Then do 5,6,7,8,7,6,5, at a second each. When you lift off each finger, the movement is perpendicular to the fretboard. If you flick sideways, you're effectively making a pull off, which isn't part of this procedure, although the two often follow each other in legato playing.