This whole article is good. I've written many headlines or titles for online media as well as for big magazines and newspapers (I was an editor of section of Glamour and of the Plain Dealer). And your points are more sophisticated (and, in my view, more helpful) than many on the same topic on Medium, which are often oversimplified to the point of uselessness: e.g., use a number in your title. Numbers can be very effective, but in my exp., even there you have to consider the context. "7 Ways to Do X" might work well on its own but not on a page with six articles with the number seven in the title.