Generally you'll be invited to media events through contacts at work. If you work for a media / marketing company then you are likely to have suppliers or clients who will be keen to invite you along. Your company may well be hosting one of these events. Make sure you use them and get to know lots of people in the industry.
As for industrial seminars, I guess you mean seminars in your sector. I would suggest looking up your relevant professional body, become a member and get involved in any seminars / discussions they have.
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