An ounce of prevention
First, you should prepare the right amount for your video, to prevent lots of painful editing later. My approach:
Alternatively, if you're recording some action, record it once or twice first, to see how you can improve your camera movements and shot framing. But also keep these until you're done editing later, because they might be the best shots.
Edit, edit, edit
In game design we have a saying. "Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." I noticed this when I was taking photos of school events. People said, "Wow, you take such good photos." No, actually I throw away such bad photos! And I edit the remainder to emphasize their aesthetic qualities and meaning. Same with video. For most horizontal-format videos, I use iMovie, which is still free on the App Store.
It's easy to find segments of your video that don't add much. You can trim them out and use a half second transition, or just jump cut to the next bit. It looks more jarring to you than to your audience.
And the magical start and end sliders around every clip let you trim out the parts where you're just breathing and thinking of what to say. Here's the idea in under a minute:
You can get deeper and deeper in editing, but that's a good start. I'd hate to give you so many tips that you never go and try. Record something, trim out the crap, and publish!
Here are the steps I use for publishing.
1. Share to YouTube
Why caption your videos?
Also you can export your captions from YouTube, so you can reuse them when you share the same video into the walled garden of Facebook. Cause yeah, if you link to a YouTube video, Facebook will prioritize your post somewhere below two-week old stale memes. Oh, sorry, Facebook absolutely loves stale memes. So YouTube links are way below those. Quick tips for reusing your captions:
I do hope this points you in the right direction for publishing your own videos. Too much information? Too little? Let me know in the comments! If this is helpful, next time I'll show how I edit vertical videos, which iMovie inexplicably cannot even.