Update: Sep 2018
The link to the infographic is dead, so I am taking the liberty to upload it here, since there has been quite a few people interested in it.
Here was a great infographic(https://training.linuxfoundation.org/images/lftc_evolution_sysadmin.jpg - link now is dead) on the evolution of a linux beginner to a seasoned sysadmin and the steps and skills that you need to gain in the process. It also have a resources included on each step with links below, so you can start your journey today.
Why is the above infographic useful? Here is another one that shows in 2013 the demand of sysadmins have increased 90% and the salaries with 9%. The trend will grow and the demand for experienced linux users who know their way with a server as well, since the internet continues to grow and all those sites need a web hosting.
Be sure to check the sites of the top companies that we have included in our best 10 uk web hosting reviews and find even more resources on the topic.
And here is the original from the Linux foundation
It is 3000px wide so right click on the image and 'view image' to check it in full resolution.