That is a great question that a lot of people have.
A great way to network with people with your similar mindset or career field virtually, I have found, is LinkedIn. I am looking to go into collegiate professorship when I retire from my current position in a few years. I am building up my network now. What I am still doing is looking up colleges that I would be interested in teaching at and sending requests to the Deans, assistant deans and department chairs. I now have a large network of leadership at the colleges near me so when I am ready to apply, I have my LinkedIn address on my resume.
Another good way to network is to volunteer or intern in the area that you are interested in. That will open up a great way to be able to interact with others in your field.