If there are 3 things you wish you knew before starting a YouTube account, what would it be?

Skill is more important than gear. Some people get the high end gear when starting out. After 3-4 months they give up.

People watch youtube for entertainment and for the personality of the youtuber. So it's important to show them your true self and make the video interesting.

It's a marathon. Many people don't realize how much work goes into a video. The first few months (or even years) are fueled by passion. If you go in just for the money, and no passion in making the videos, you would give up very quickly.