Originally Posted by: martiniconqueso

I am utterly new to guitar so it's likely I'm just not "getting" something, but anyway - I have some difficulty fretting - specifically changing chords - while standing.[/quote]

What kind of guitar? Have you tried adusting the strap?

Originally Posted by: martiniconqueso

If the guitar is a lever in this scenario, my belly is the fulcrum. It feels as if my strumming/picking arm (my right) presses the body of the guitar back towards me, and levers the neck away from me, while I play.

[p]I think some or all of this is simply too much tension in your technique.

Your posture, arms & hands & all your motions should be as relaxed & minimal as possible. Rest your arm lightly on the the guitar body. So lightly that it won't move the guitar around very much or at all. This is where proper strap adjustment can help. You are aiming for the guitar to remain almost if not completely stationary.

I describe & demonstrate good posture & mechanics in this video. I'm sitting, but it's the exact same principle.

https://www.guitartricks.com/lesson.php?input=13958

[quote=martiniconqueso]For example, going from simple Am to simple E I tend to keep my middle finger on the G string until I have my index finger in place. Makes the changes less smooth than it seems like they should be.

The motions required to play guitar are very minimal. Finger placement during chord changes need to be as simulataneous as possible. In order to do them quickly and efficiently you need to repeat them slowly & correctly as many times as necessary to get them into muscle memory.

Form A minor chord. Strum once.

Change completely to E chord. Strum once.

Repeat slowly until you get it all done smoothly & with minimal motion.

Gradually speed up once you've got the right motions down!

Hope that helps!