I have been going on this for about 2mths. I am trying C-F and for F i usually put down in order of ring, middle then index last. I lay my index almost right on the side and very close to the 1st fret bar so after I've played it a few times I have two lines on the thumb side of my index finger. Seems to be working out well, my only challenge with that pesky F chord now is to be careful not to mute the b string with my middle finger.