https://useplaintext.email/ makes a good argument for plain text email. Here's some standard things relating to that.
That's where your replies have a thing at the bottom that copies all the previous emails. Adds a lot of clutter for no reason since the whole context doesn't have to be in every email. The preferred approach is to quote parts of the previous email as they come up. This is easier if you do your settings so only the last email is quoted so you can then just move and delete what you need to.
People like to wrap at 72 columns. I'm not sure why, but aerc automates it.