One of the best ways to become an “expert” is to get involved with different Telecommunication Topics. Look at questions and see the different answers.
At the time of writing we have several hot topics that should be looked at: Data Centres, SDN, NFV, Cloud (XaaS), Virtualisation, Openstack, OpenDayLight, Big Data, Web3.0/4.0, 4G/5G, Routing Protocols (MPLS-TP/-TE) and the emergence of Quantum Computing.