A phrase that i have lived by for most of my adult life has been, if you keep doing what you've always done, you will keep getting what you have always gotten. This goes hand and
with social media. There is something to be said about consistency but when that starts to fail, don't be afraid to get a bit wild. If you have gotten into a bit of slump when it comes to your marketing, give something a shot. Try new post styles, times etc. Go crazy, see what others are doing and try that. If you keep doing what you've always done, you will keep getting what you have always gotten.
Enjoy and let me know what happens.