What are some bad habits I should avoid developing as a new swimmer?

I’m just starting to learn how to swim properly, mostly focusing on freestyle (I’m hoping to do a triathlon this year). I’m taking group swim lessons and swimming on my own during the week. The amount of advice about technique, breathing, body position is a lot to keep track of, so I am trying to prioritize that I am focusing on. What are some common bad habits that people develop early on that are hard to fix later?

Thanks!