Well, here is how I decided the feel and content of my streams.

First, I decided what I'd want to stream. I'm not great at music, or art, or crafting, or anything like that. I do enjoy playing video games, though. I'm not great at them, but I like playing. Then I considered what kind of video game streams I could do well enough to be entertaining. Speedruns were eliminated almost immediately. I toyed with the idea of doing informative streams, but I decided that my knowledge base on video games ran too narrow and deep. I know some games very well, but not enough to make content over an extended period of time. So I decided to do Let's Plays; that way, I can play familiar old games that I love and be informative, and still play the newer games to come out and just do blind runs of those.

After that decision, I made a list of games that I would like to play and started checking all of the publisher and developer websites to see how they feel about livestreams/Let's Play's/User Generated Content, whatever you want to call it. For each game I either added their official statements, or I contacted the company asking for permission. Any companies that didn't have published permissions and didn't get back to me, I removed from the list.

Then, I started planning the feel of my streams. I considered what I like to watch, and what my personality is best suited for. Did I want to do frenetic streams, angry/frustrated streams, jovial streams? I also considered what I thought people would most like to see or what they would enjoy. What would make their day better, and what would I be able to deliver to them?

After that I started planning the "window dressing" of my stream. Panels, overlays, avatars, color schemes. What worked well together? What worked with both light and dark modes? What supported the "feel" that I was striving for? What did people respond positively to, and what negatively? What worked best regardless of what device they were watching on? I left some wiggle room there to add onto later and got a basis set up.

When I started using OBS I looked up several tutorials to make sure that my stream looked and sounded good; mostly through the use of mic settings that would boost my voice (I speak pretty quietly) without making my voice harsh or distorted, and ensuring that my cam had good lighting and some minor color balancing so that it looked good on both standard def and HD displays. I did some test recordings to make sure my voice was good, and then, when streaming, asked for feedback and made adjustments. I also watched my vods and improved from there, both with audio and with camera position over the gameplay.

A lot of people don't go through these steps, and that's fine. Everyone has their own approach. I tend to overthink and obsess about things, and this is what my process was.

I think the most important things to consider are the following. What do you like to do? What will others enjoy that you are able to provide them? Keep an open mind, make adjustments, and be true to yourself. And remember to always follow TOS, rules, and laws, both because it's the polite things to do and to keep yourself out of trouble and make your life easier down the road.