At CAPSiDE I've learn quite a bit from here and there. Not just system administration, but how to deal with clients, how to do support, understand the needs of the client, give them the best solution for their problems, etc.
When I started at CAPSiDE I had panic to answering calls from customers. I was nervous about the fact that they could ask me something I should know, or not understanding a thing about what they wanted, missing some important information about their request or even not making the right questions to fully understand what their needs were. In a few months the fear started to fade out and I was more confident when answering calls. Knowing the name of the clients, how they have their infrastructure, what are the most common requests, etc. made the work way easier. At the end of my days at CAPSiDE I had no problem doing support. Even more, I enjoyed answering calls from the clients that requested our help to solve their problems. Was kinda satisfying.
Dealing with clients is not easy, but summarizing what I think are the most important points that helped me to give a better: service your clients need to trust you, you need to have a good communication with them and a really high technical knowledge about what you are doing.
Each of this points enforces the others. Lets see each one:
If the client trust you, thinks are waaay easy. It must not be a blind trust but something you have earned. In meetings, when the clients ask you for your professional opinion, when you contact them proposing new improvements on their platforms, etc. trust is essential. You can get things done way quicker.
A good way to earn the trust of your customer is being honest all the time, for all good and bad things. This is related with the point below.
What the client must perceive is that everything is under control, that you care about their problems, that when they request a change or something new a reasonable amount of time is spend talking with them and trying to understand their needs. If they are worried about something (even if there is something irrational that technically does not make sense) you must take extra care and time to transmit them confidence, describe the procedures involved and what you are going to and how are you going to react if something goes wrong.
This job is not only done by the operation team but the commercial team also can help and transmit this confidence to the client. The reputation your company has in the sector can help you a lot in that sense.
Transmit what you are doing. Keep the client informed all the time. Be honest. Always. Even if you do something wrong; never try to cover your errors. Shit happens, human errors occur and everybody understand that. Don't fool yourself trying to hide something to the client that went wrong. Call them. Explain what happened and the measures that have been taken to solve the problem. Transparency is always a big win.
Not only transmit the bad things but the good ones. A important change (trivial or not) has been done without loosing service. Let the client know. Don't be shy and explain even the smaller improvements you have done for them. This give them the feeling that you care about them and their systems even with things they don't know about. The problem in system administration is that if you do your job right nobody notices anything. Report everything.
Most of the problems could be solved if you have had a good communication with the client. Call now instead of tomorrow.
High technical knowledge
To transmit 'good vibes' to the client, to justify why the technical decisions have been made this way, to be able to make understand a client what is a bad idea and why, to implement what has been sold, to quickly react to problems in a production environment, etc. To do all of that you need to have a deep knowledge in the technologies and best practices. This does not mean that you need to know everything all the time. Of course there are things that need to be checked in the documentation. But if you want to do a professional job, and to be able to convey confidence and have a good communication with the client, it is required to have a deep knowledge about what you are talking about.
This is just some of the points I've learned while working at CAPSiDE. They may seem obvious but as always is more enlightening to learn this things by your self than read it on a book (or a blog post ¬¬'). Hope you can get the idea, though.