Melanie Coulson has some tips on why these two platforms are important and what you need to know about them.
5 fundamentals journalists must understand about Twitter
5 fundamental things journalists must understand about Facebook
It’s interesting that the one common thing for both platforms (apart from knowing your audience) is the idea that it is images that capture attention more than words.
I have certainly found this with my own work on FB — images that are funny/novel/arresting seem to get the most attention. I suspect my Twitter following is more wordy than the average, because I haven’t seen the same response on that platform. (Though I concentrate less on images.)
If you are thinking about playing with images, it’s important to remember how they are likely to be seen. Twitter pictures, for example, show the middle third of the image, not the whole thing, in the feed. Something to consider as you’re adding text, and uploading the same pictures to different platforms. I would recommend editing your images for different platform use.