Hi.
There is not an easy answer to such a question: there are many Microsoft technologies and you have to choose a small subset of them and focus your training and studying efforts, therefore being an expert in every Microsoft technology is pretty impossible.
There are several free resources that could help you in learning Microsoft technologies, such as
edX or the
Microsoft Virtual Academy.
If you're interested in a Microsoft certification, I suggest you to visit the
Microsoft Learning site.
Bye.
Luigi Bruno
MCP, MCTS, MOS, MTA