"Places where people hang out" is a very general question and as my readers know, I am very specific and strategic. First you have to ask yourself, "who is my target market?" Because I can tell you where actors hang out, but if you're an actor, actors don't hire you. So really your question could be, "where do casting directors, producers, directors, and executive producers hang out?" If you're another classification you'd ask the same question based on the people who hire you.
Once you know your target market, then you can research the entertainment organizations, philanthropic organizations, clubs (and I mean sport, nature, parent type clubs not Sunset strip clubs), unions, etc., where they congregate.
As far as leaving postcards around, that's like a needle in a haystack. People who are hiring have so many relationships with people who are inviting them to things. Why would they pick up a postcard of a complete stranger and say, "I think I'll take 3 hours out of my valuable time, to go see this stranger." Not to say it can't happen, but you can spend your money and time in a better way.
Again, you're better off taking those postcards to a networking event and handing them to people once you have a conversation with them and build rapport.
If you want to put a comment in the section, telling me what classification you are, I can be more specific about what organizations you should check out.
For more tips and articles by top entertainment industry career coach, The Greenlight Coach, visit www.TheGreenlightCoachBlog.com