How to become a system adaministrator?

Hello Everybody. I’d like to become a Systems Administrator. This is what I have been doing so far: A.S. degree in Comuters Systems, 7 years as Desktop Support Level 2 Analyst (harware, desktops laptops, printers) and (software, OS, windows 7, 8) AD tools users and computers (move machine name between containers, apply GP, reset passowrd, identify security groups) asset management, little VB scripting, A , Network , Security , MCP, and MCTS Windows 7. I am currently going for MCSA 2008 Server and going for the upgrade to MCSA 2012>MSCE 2012. I took the 70-640 and failed…planning to retake in 1 month. Any advice on what to learn,what practices to start, and training to become a systems administrator? Thank you!!!!!