How to learn/master (tutorials) for managing a VPS? - newbie VPS user [closed]
These are some areas/questions you should concern yourself with:
Security. Is the firewall locked down? Is there a strong root password? Do users have the lowest level of permissions possible to accomplish what they need?
Backups. What happens if my hard drive crashes? Can a hacker delete my backups?
Disaster Recovery. What happens if my host is unavailable due to an extended power outage at their NOC or a natural disaster? Will my clients understand or will they expect me to have another solution. If so, what is my plan?
Monitoring. If I'm not the road, how will I know if my server is down? What can I do about it if that happens?
Patches and Maintenance. How do I know if there is a new patch available for my OS or one of my key applications? What is my plan for applying those patches? What other maintenance tasks do I want to do weekly or monthly such as archive log files?
So, armed with those areas and sets of questions, your next task will be figuring out how to answer those questions to your satisfaction.
I would recommend you purchase a beginners books such as Linux Administration: A Beginner's Guide to start, and if you want more information on various aspects (security, disaster recovery, etc.) either ask more pointed questions here or look at some other books.