I know it sounds odd, but I don't. Mostly I look for info on specific techniques, but they often include tips on general techniques as well. For example, here are a couple on cell/lacing effects.

https://youtu.be/E4yCzQ-VvhE https://youtu.be/K4VrQLZQLYY

But here's the one you absolutely should watch first: safety.

https://www.youtube.com/watch?v=mr1E9v_9fww

It's not worth freaking out over, but I'm a safety-first kind of guy. The Alumilite videos are generally very good (especially this guy) and they also make one of my favorite black/white opaque dyes. Stone Coat also has some really good ones, even though they're usually for much bigger pieces - tables and countertops - than anything I'm ever likely to do.

https://www.youtube.com/c/EricStrebel more higher end molds, he does a ton of other making too.. but molding/casting could be resin, plaster, wax or cardboard.

https://www.youtube.com/c/RobertTolone MOre about the science/art of the mold itself

https://www.youtube.com/user/TheFluffinAmazin he makes mostly dice.. but its approachable.

https://www.youtube.com/c/EvanAndKatelyn not the best at it, but entertainable.. they use resin to cast but more to cover and as an art media..