As I've learned thus far there are three important areas to achieving success within customer success: soft skills, hard skills, and attitude.
Communication is absolutely the biggest skill to have, at a typical customer service role, or customer success. The job is centered around telling people how to fix things. If you can't communicate well then you'll do a pretty bad job. You have to be able to very clearly walk people through processes. Communication is also great when talking with upper management about how to improve efficiency, or when proactively attacking potential problems customers may have. Listening goes hand in hand. You have to be able to effectively listen to what the customer is saying in order to help them, and cater to their specific needs.
-well adept at using company product
The hard skills are more obvious. In a position like this, your entire day will most likely involve using technology. A headset, using a computer, email, calling people, taking calls, etc. Essentially everyday technology. The second part can be very different. Your company might be selling something else in tech, or it could be something completely different. It's important to know it like the back of your hand so you can solve any potential problems people might run into.
Attitude comes third to the other skills, but it is still very important and impactful. When customers call in a fluster, it can be easy to get stressed out or empathize too much and you don't know what to do either. But if you can remain calm, understand where they are coming from, and be patient with them, you will have much more success in solving their problems. They will also have a good association with the company.
With keeping these three things in mind, you are far more likely to succeed in a customer success role.