When you are in a certain field of work, you are going to be doing tons of research. That means reading a lot of journal articles. (And when I say a lot, I mean it. When I did my thesis I had a stack about 5 or so inches high of articles I was reading.) So you get your main info by reading these articles.
Once you read the articles that apply to you, you usually end up contacting the people who wrote the articles (or at least I did when I was doing my thesis).
You make friends with them (as long as they aren't too cut-throat) and get to know what the latest developments are.