being a relative novice I can tell you what I do and how I got to where I'm at. I fret the 1402 by using the index finger for the "1" and middle finger for the "2". On the C string I put the middle finger on the third fret and the pinky on the fourth fret. I realize the middle finger is useless in this formation but when I put it down on the third, the pinky follows to its place more easily.
At first I couldn't do this shape like many others, but I just used the rote method. It sounds laborious, but when you time it, it only takes about five minutes. So what I did was just form the chord 100 times a day. Again, that sounds horrible, but it really goes fast. I just make the chord, strum it, shake the hand out, and do it again. After a few days everything is fixed.