Based on a Track Maven study of 1.5 Million posts and 6000 brand pages here are a few quick pointers that can help you create the engagement that you are looking at for your brand.
Messages that are creative, funny or create a level of curiosity in the users mind are most liked and commented on or shared. It is not advisable to make it too wordy as long messages are often not read, though posts greater than 80 words garner two times the engagement.
Asking questions as shown in the post below helps brands engage the audience in the right context. Posts with exclamation get 2.7X more engagement.