Watch the Plucking with Fingers online guitar lesson by TrueFire from Play Acoustic Guitar 4: Rhythm Approaches
Plucking with Fingers - Technique #7 is a video guitar lesson presented by Vicki Genfan and is sourced from Acoustic Rhythm Survival Guide.
For this exercise, we're going to pluck one bass string (4, 5 or 6) and the top three high strings (E, B, G) all together. Look carefully at the video to get your right hand in the correct starting position. The action is not really 'pulling' out of the strings, in fact your thumb is moving in a downward direction while your other fingers are moving towards the palm of your hand – as if you were gently closing your fist.
Again, watch for unnecessary tension in your fingers, hands and forearms. Don't aim for volume, but at first focus on clarity and picking or 'plucking' all strings at the same time.