Strumming Or Picking Style

We feel relatively comfortable now playing a right handed guitar left handed and holding the guitar left handed. We can make the major chords, A, B, C, D, E, F and G with the right hand. What about the left hand? How do I hold the pick? What type of strumming technique do I use? There is no particular technique and I have never seen any particular instructional guide for what is right and wrong for this unorthodox way of playing the right handed guitar left handed. I can only tell you what I do and how I developed the technique that I use.
"Flat Picking" is a term used to play mostly single notes combined with chords for a lead acoustic guitar part. If you want to hear examples of "Flat Picking" then listen to any song by Doc Watson. As far as picking the lead, there is no difference in the way you hold the pick left handed and the way a right handed player holds the pick. Between the thumb and the index finger. Problems may arise when the palm of your left hand tend to muffle the strings. To avoid this, position your left hand with the wrist pointing away from the strings. In other words you may have to bend your wrist much like you do when you write left handed. You may come up with your own method but that is how I do it. Another problem may be in the method that you learn the lead part. I have learned by three methods. Tabulature, being taught one on one by someone else, and figuring it out on my own. Tabulature is a good tool for learning scales and exercises. You just have to interpolate what you are reading because again it is written with the right handed player in mind. Left handed tabulature is available but not useful because you are not really playing the guitar left handed in the context that it is written. Believe me, it's not as hard as it sounds. The easiest way to learn a lead lick is to have someone teach you one on one sitting across from you.
"Finger Picking" is when you play multiple strings set to a rhythm that gives the melody a fullness much like a piano where you separate melody and bass notes. Classical guitar music would be a good example. I hold the pick between the thumb and index finger and pick out the bass notes simultaneously with my middle finger. This method works well for me since I have tried everything else to no avail. I even tried the three finger "Scruggs" banjo style but it just sounded like a banjo roll.
"Strumming" rhythm may be a challenge at first for the left handed player because you will have to concentrate on picking using an up stroke instead of a down stroke as a right handed player does. Just remember that when you play a strum you will normally start on the low E string and strum up to the high E.