Ask HN: How to be a freelance developer?

- What are the dumbest mistakes newbie make? How to avoid them?

- What are the must know things to earn sustainable income & continue freelancing for a lifetime?

- What it takes to be a good freelancer?

- Any resources that will help who is starting with freelancing in general without prior employment history?

- Help me, Make this post freelancing guide for dummies. Cause I know I am missing something.

Thanks a lot, in advance.