I'm not sure I would have called this infographic How to Create Perfect Posts; however, it does have some great clarification on what best practices work for updating your blog, video and social statuses online. This is the fourth iteration of their popular infographic – and it adds in blogging and video.
Utilization of imagery, call-to-action, social promotion and hashtags are great advice and often ignored as marketers just work to broadcast their content. I don't think it's a surprise that the best results are attained when you pay close attention to the strategies you're deploying and testing whether or not they work well.
There's really no perfect post that works for everyone – including the timing of the posts. We happen to publish quite early in the morning and it works very well. We're in the Midwest so by publishing early we can reach across the pond in the afternoon, reach the East coast in the morning, and reach the West cost… the optimum timing for your business or publication will vary on whether you're local, national, international and when your audience is paying attention. If I were a venue; for example, I may want to publish in the early evening when folks are planning their night.