Get in the habit of composing your emails in a specific order. My preference is:

Write the title, upload attachments, write the body, choose the recipient(s).

Doing the recipients last in particular gives you that extra few seconds to consider all the other elements so you can realize and correct any mistakes before hitting send. I used to do shit like send w/o attachments or send to the wrong/not all of the intended recipients all the time, but following the same order has basically idiot-proofed it against myself.

10/10, do recommend.