Great visual by SalesForce to show how to write an engaging post on Facebook. Personally and after some years exploring this, the best way is basically to upload a cool image (it’s more visible in the news feed than a simple text for example) + short text (even shorter than a Tweet) + Effective Call to action (depending on your goal) + link (Use bit.ly to shorten it and keep tracking)
Actually this model merges perfectly with the popular AIDA model
A – ATTENTION-> A cool image is the best format to get the user attention in the news feed due to a bigger space and a easier visualization.
I – INTEREST -> Interest and Desire shows pretty closed here. Basically, a short but interesting and direct copy is the best way to achieve this. Think that people have no time to spend. Be direct and clear. Use formule like How to, Did you know, What do you…
D – DESIRE -> (INTEREST)
A – ACTION -> Write a short but effective call to action + a link to know more. If the goal you pursue is liking or commenting, ask for it within the call to action and don’t include any link.