I've known for a while that I hold my pick differently when strumming chords as opposed to picking single notes. I decided to do something about it today.
The difference is subtle enough that I don't have to pause to change my grip when switching between them. The transition is more or less seamless, so I was never inspired to take a closer look. But I noticed that the way I hold my pick when strumming is more stable, and my single-note picking would probably benefit if I could apply it there too.
When I pick notes, I tend to hold the pick between the pad of my thumb and the pad of my first finger. This draws the pick away from the palm of my hand, but I feel like it allows me to pick more comfortably when palm muting. When I strum, I tend to hold the pick between the pad of my thumb and the side of my index finger. The pick stays under control, and I can use only the motion of my wrist for playing.
The problem with my current picking technique is its lack of stability. Because the pick is farther from the palm of my hand, I end up using motion from my fingers for picking instead of just my wrist. I've seen some great players pick by moving their fingers, but I don't like it. I feel like I can get stronger, more consistent notes if I can isolate my wrist motion.
My only obstacle is the palm muting, particularly on the high strings. When I turn my hand to get enough meat on the strings to mute them, I have to pick at an awkward angle, and it's difficult to use my wrist motion. I'll keep at it though; I feel like I made progress today.