increasing engagement for videos

generally

• choose a good thumbnail
• try to catch the viewer's attention within the first few seconds

on Facebook

• use a square aspect ratio [2]
• assume that at least some of the users will watch with the sound off [2] (as some users have it disabled by default), so be sure to use text (titles and/or captions) to "hook" people, as well as what's happening on the audio side
  • do a test, and watch your own video with the sound off, to make sure that most of the content is legible with the sound off
• choose a title that's easily searchable
  • (I don't personally search for Facebook videos like this, but some people do)