Shameless promotion of my own video on setting up OBS; I created this for some of my friends and colleagues when we first started moving to all online teaching:
https://www.youtube.com/watch?v=n5KGeiw3KV4 I will note that toward the end of the video on some finer tweaks, my scene was not correctly showing OBS cropping.
That said, this article does a great explaining the Twitch integrations. If you aren't looking into Twitch streaming, that portion can be ignored.
I've been using OBS for creating lecture videos for years. I use it mostly because when I started, it was one of the only free quality stream capture tools out there and I'd seen a few of the early Twitch streamers using it. Since I was teaching, I wanted to imitate the Khan Academy style drawings. The article uses an iPad, but I've gotten pretty comfortable with GIMP and a small Wacom tablet.
My setup (my equipment is a bit old, so it doesn't look like they are still sold):
* Samson Meteorite microphone: https://www.trustedreviews.com/reviews/samson-meteorite
* Wacom Small Pen Tablet: https://www.amazon.com/Wacom-Intuos-Touch-Tablet-Version/dp/...
* GIMP: https://www.gimp.org/
Your two most absolutely crucial components are your sound and your lighting. The sound should get picked up well so the viewer doesn't need to adjust their volume to listen. I know some of my videos have fallen short in this quality because of the mic's positioning.
Also, think about your voice and enunciating your words. Since my lectures are public, 20% of my channel's traffic comes from India and Germany. You don't need to necessarily slow your words (like I did when I started), but you want to make sure each word can be heard cleanly. You may not realize you have a hard to understand accent because it just seems natural to you. You can also mitigate this with subtitles (I've used rev.com for ADA compliance).
Lighting is the other important aspect because if you are going to stream your face, it needs to look presentable. You don't want the lights shooting directly on your face though because that can wash out you texture and color. Like in the article, you want to bounce your lights off a white surface for a softer illumination. I'd recommend reading some indoor filming techniques to get a good setup, since you are effectively on camera.
Likewise, know your eye line. I like to have my camera at just above eye level so when I'm lecturing it looks like I'm talking to my students, rather than looking down/up wherever your webcam is. This was also a tip I gave to a friend last week before he presented at a conference. Acting for the Camera is a nice book you can peruse for small tips like understanding your frame.
Finally, you're going to be very clunky when you start, even if you are at extroverted person. You'll need to become comfortable performing in front of the camera no different than in front of a classroom or audience.
Here are three videos illustrating this point:
[1] One of my first videos https://www.youtube.com/watch?v=PEYOixCgGHg
[2] Literally two months later, notice my increase in cadence https://www.youtube.com/watch?v=ltav5tp43RY
[3] Five years later https://www.youtube.com/watch?v=Dggl0fJJ81k
Once you start, watch some of your videos to see what you think is wrong or weird with them and try to improve.