Eliza asked what my mission was for each of my social media accounts and how I balanced life and book content. Those are both really great questions, so I'm going to go through the main social media mediums.
Keep in mind, though, that even though there are differences between each of these sites ... You could make any of them fit your purposes. The main factor is where your audience is and if you're engaging them.
However, I do tend to treat each of the social media differently with my kind of content, so I'm going to tell you what I use, why I got it, and what I post.
I've had Facebook the longest, but the reason I got it was to make my author Facebook page. There, I share my blog posts, some occasional writing updates, sales of mine and friends, and some witty writing-related things. The writing memes and such I'm getting better at sharing. But despite all the algorithms being against us and whatnot, I still get a decent amount of blog views from Facebook, so I'm going to keep at it for now.
As far as posting on my actual profile ... I really don't do that a whole lot. I'm trying to get better at sharing bits of life there! But it's one of the places that I've friended the most writers and get a good picture of what someone's life is like. (Provide they post, unlike me. :P)
I do enjoy being a part of Facebook groups and have several of my own groups as well. Facebook parties are also completely one-of-a-kind and can be successful as well. So those two things alone make Facebook pretty invaluable. Plus, it still tends to be the most universal social media.
I had several friends tell me I should get an Instagram, and I resisted for a while. Because 1) I don't consider myself a good photographer, and 2) I hardly used my personal Facebook as it was. Well ... I love Instagram. xD
I have my author profile that has turned into mostly a bookstagram and a place for me to keep up with a bunch of other writers and friends. It's also the only place I've messed with the "stories" feature at all. (I love them!!!) For whatever reason, I don't like them on Facebook, and I rarely cross-post from Instagram to Facebook.
I also use way more hashtags on Instagram than I would anywhere else. I used to think they were obnoxious, but on Instagram at least, they really do work well to categorize things. Provided you're using established ones and not hashtagging randomly just for the fun of it. (It's a skill ... that I'm still developing.)
Just this year, I started a second Instagram account for more personal things. I want my author profile to stay pretty, so I don't post everything that comes to mind on there. My personal profile is more for my health journey and my day-to-day life.
Obviously, many people don't categorize their social media quite that much, but I've found that it works best for me. I'm posting more on Instagram in general ... but perhaps less on each individual profile than I otherwise would have. Even for that, there seems to be more community on Instagram that doesn't rely on you knowing the person first.
I am super inconsistent on my Twitter usage. I will cross-post here from both Instagram and Goodreads sometimes. I try to share some of my blog posts, witty writing things that come to mind, writing updates, retweet meaningful/funny things ... I still keep it mostly writers-life themed, and I don't share pictures hardly at all.
I have a similar following on Twitter than Instagram, but less interraction overall. If I were more frequent and a little more witty about what I did ... I think I would do well. Some people have made very good niches there. But it's about how relatable and shareable things are to do well. People have to relate.
I love Pinterest, but I don't use it nearly as much as I used to. I have it primarily to make WIP aesthetics. I also use it for personality typing graphics and other random interests of mine.
However, I do have multiple boards that have writing-related articles and information on them so that other people can be benefitted by my profile as well. Apparently, by pinning for the sake of other people and pinning blog posts and whatnot, some people generate a lot of traffic from Pinterest. I've never been quite dedicated enough for that, but have seen tiny results off the tiny things I've done.
While I do have a YouTube, I don't use it a whole lot. I used to do a lot of video interviews, some bookish reveals or hauls, and one or two topical videos. However, I find that it's much faster for me to stage a photo than to stage a video. My house has horrible lighting and a video requires my face. Yeah, no thanks. xD Some people really love the vlogging and do well with it. So maybe this is a medium you would like. I always think I'll use it more, but it's something I never get around to.
I felt like that was a lot ... but it should be pretty obvious that I use Facebook and Instagram the most! There are others like Goodreads and Snapchat that can be used beneficially as well. Even though I have accounts with those, I use them more for my own amusement than for the benefit of my endeavors.
It really comes down to what you're comfortable with and what you're looking for. There's probably a social media out there for you. ;) It is smart to have a reason for getting another account, though, instead of having one of everything just because.
As far as the life and bookish balance ... I try to stay personable in everything I post, but also keep a professional/consistent look to things like my Instagram. I think everyone has to find their own balance for how much they post about their books, books their reading, their daily life ... how vulnerable they are. All of that is dictated by my own inclinations and comfort level to a large degree. But getting outside of your comfort zone a little is often a good thing as well.
I'd also encourage consistency! Not just with posting, but also with things like your handles. I'm @abitheauthor basically everywhere. It keeps my life simple. Or at least as simple as having a dozen social media accounts can be!
Let me know where I can follow you! What social media is your favorite and why?