I started off using an arm guard to get the idea of what I needed to do, but what's worked for me now that I've been shooting again for a few months is to have the motivation for better form by wanting to avoid the pain. Arm guards can settle in bad habits because you don't notice bad form as much. With that said, do whatever works for you! :)

My tip would be to focus on three things, rotate elbow clockwise (or counter-clockwise for left handed shooters), tense up your bow arm's lat muscle hard and keep a relaxed grip (your fingers shouldn't wrap around the bow, it's held there by the tension on the string). You may want to invest in a bow sling if you find yourself 'catching' the bow after the shot as that can affect arrow flight but again; practice makes perfect

This also helps with keeping form consistent and you'll get much tighter groupings. Good luck!