After completing a Digital Marketing Strategies course and starting a social media internship, I have learned a lot about when to post. If you are first starting out, you have to be experimental and post at various times of the day on various social media outlets. Also, try playing with the frequency at which you post on each site.
A rule of thumb is, you can almost never post too much on Twitter. Try to space out your tweets a bit if you are trying to post a high amount at first, but Twitter is a never ending feed of information and your followers are most likely not only going to see your tweets. When posting to Pinterest, remember that it is highly used on Saturdays and that you shouldn’t post too much to overcrowd your follower’s feed. On your Google+ page, posting weekdays before noon is usually best. Google+ is also extremely good from an SEO perspective, so even if you do not have a large following on Google+, post everything and use hashtags (2-3 max per post). Facebook posting can be tricky to figure out. Keep in mind that engagement grows higher on the weekends. The “new” feature of promoting posts for your Facebook page that started in late 2013 has really changed the game when it comes to posting. I have learned to not be afraid to post multiple times a day. It will not annoy your followers because those following you will likely not see every post you make. When it comes to boosting your posts pick a post that you feel is going to be shared and liked a lot. Also, boost posts that you would like to promote the most. Not every post needs to be promoted, just be strategic and think of which posts you want to make sure almost all of your followers and more will see.
After doing this for a month or so, check out the analytics provided for your page. They should show steady statistics after a while and thankfully, almost all social media sites provide those analytics. Especially when starting out, note when you get the most response and feedback from your posts, that is what will overall tell you when the best time is to post for your audience.