In my hiding from Sun and Moon spoilers, I've come to wish all Youtubers, journalists, and artists would adopt a system to alert viewers of spoilers in videos or articles. It's pretty simple too, but some people just like ruining it for others.
1. Keep spoilers out of any thumbnails of video/article/artwork. This also includes silhouettes. I've seen Youtubers especially put silhouettes in thumbnails to prevent spoilers, but they're still spoiling part of the Pokemon/character for you. In addition, keep spoilers out of the titles. This would ensure that anyone could safely browse sites without being spoiled by the outside of something. Spoiled after you enter the content is one thing, but being spoiled when you aren't even in the content is a whole different story.
2. Have a short 5 second intro or short paragraph before an article that reports on the types of spoilers that will be shown in the journal or video. I completely avoid all the spoilers in fear of Pokemon spoilers, but it would be nice to know if something contains Pokemon spoilers, story spoilers, move spoilers, stat spoilers, or all of the above. I don't really care about move or stat spoilers as long as they keep the new Pokemon out of it.
It's two steps! THAT'S IT!