How to be a GREAT social media manager.

I'm currently in the process of getting someone to manage all of my social media accounts; it's not my forte and to be honest it's taking me way more time than it should so I think I'm better off leaving it to someone who can give it the time it deserves to get results.
Problem is, I'm a bit controlling so I want a really good understanding of what's required for the role before I hand over the reigns. I'd like to think that people who market themselves as a social media manager know what they're doing but in my experience you just never know and how easy is it for them to post articles and ha ha jokes without really looking at WHY they're doing it?

So I've been doing quite a bit of research on the subject and I think I've got a really good understanding of the things I'd need to make sure they were doing and as you guys have given me so much help already, thought I'd ask you for your input again!

These are the things I think a good social media manager should be doing - anything to add or correct?

Notice what people are saying about your company.
They should be searching hashtags and mentions and dealing with any feedback - positive or negative. Do people expect their social media manager to be on call 24-7 or is this left to you at weekends etc? As we know, social media doesn't just stop when it gets dark!

Check your insights.
Facebook and Instagram both provide really important, specific information on your posts and it's really important that that's utilised. It means that they can see if what they're doing is working or indeed if it's a big fail.

Check others in your niche.
It's good to keep an eye on what the competition are doing, but not in a creepy way! Copying isn't the way to go mainly because it's wrong but also for me, I believe success comes from authenticity which isn't the case if you're copying someone else. You can share other posts but always referencing them as the original source, and you might also get some good ideas for your future posts.

Make friends.
Social media is really quite similar to a school playground or conference if you want to put it in adult terms! It's important that you connect with others in your niche so that you can build rapport, learn from them and even start to interact with each other which will help you to gain new followers who are interested in your product/service. Social media networking is really quite crucial to the success of your page(s) so if you can do it without coming across as stalkerish then all the better! Following your competitors on Instagram, writing comments (relevant - none of those generic ones) and liking their pictures are all valuable networking tools.

Hold the criticism.
It's easy to get caught up in drama, politics and criticism but you need to work with someone who knows that they should avoid this at all costs. Lots of people are rude and downright wring on social media, they have much more bravado than dealing with someone face to face or over the phone, however don't get caught in their trap! You should never comment on controversial posts (unless this is how you want to make a name for yourself, I personally don't) and if someone criticises your company or brand publicly you need to smile first and then respond. The customer is ALWAYS right and don't forget how easily things spread on social media. Giving an irate customer could see your reputation in tatters before the day is out. Not worth it.

Churn out awesome content!
It's a basic one but I'd hate to get stuck with someone whose posts weren't inspiring or creating the vibe I was after. It's important to know that they're aware of a variety of ways to communicate with an audience and really knows what posts get the most reach, engagement and ultimately get people to take action.

I'm sure this list isn't exhaustive either - what's on your list?