GNU/Linux is a free operating system. As a Linux expert, you'll improve your computer skills, be able to use a system completely customised by you to suit your needs, and have better chances of landing a good job in the IT & Computer industry. The following steps will guide you to start at being a Linux expert. Rest assured, the journey is long and fun.
Use a GNU/Linux based operating system as your main.
A lot of IT, Computer, Physics , etc. students install a Linux distro as a secondary operating system on their computers. If you want to be an expert, Use it as your primary operating system.
Try different distributions.
GNU/Linux has thousands of distributions, try major ones. Like Debian and Archlinux
Use Terminal to solve problems.
GNU/Linux is a terminal-based operating system. If you want to be an expert, you need to learn how to work on terminal.
Learn a Programming Language.
Programming Languages let you make better tweaks to the system and to fix what you need to. Learn main languages of the Unix family like C, C++, Python, and/or Bash.
Try different Desktop Environments(Graphical UIs).
GNU/Linux has thousands of X Desktop environments like GNOME, KDE or XFCE.
Use IRC channels to get support.
A lot of Linux distributions have their own IRC (Internet Relay Chat) channels. You can ask your questions there.
Look for a Linux-related job.
(Go to Openhatch)