As a complete beginner, what are common pitfalls in server administration for website maintenance?

Hello everyone, I'm quite new to the world of website maintenance and cPanel management, and I'm hoping to get some guidance from the experienced folks here. I've recently launched a small SaaS application, and in an effort to keep costs down and learn the ropes, I've been trying to handle all the operational aspects myself. This includes everything related to our 'Website Maintenance & cPanel Management Services' internally.

While I'm eager to learn, I must admit I'm feeling a bit overwhelmed, especially concerning the server administration side of things. I'm constantly worried about making a critical mistake that could lead to unexpected downtime, data loss, or even serious security vulnerabilities. I'm realizing the complexity involved in maintaining a robust server environment, and it makes me wonder if I should have considered managed services from the start. So, as a complete beginner, I would be incredibly grateful if you could share your insights. What are the most frequent pitfalls, common 'gotchas,' or critical mistakes related to server administration for website maintenance and cPanel that someone in my position should absolutely be aware of and strive to avoid?