The absolute best way for techies of any stripe to network, IMHO, is through user groups and meetups. Start going to a local programming language users' meeting, Maker/Dorkbot events, etc. -- and participate.
Ask questions, share code, give an unrehearsed five-minute lightning talk, whatever. Just make sure that people have a chance to notice you, and see you doing something interesting. If you make a habit of doing this, you will start developing a professional network, and opportunities will get sent your way.
My father often tells me to fish where the fish are. In this case, fish are people who a) have money and b) are willing to give it to you to fix their problems.
I have not been to an American user group recently but my sense of things is that there are other places where the fish are slightly more plentiful.
(Hint: they tend to hang around each other. Observing one or even asking for an invitation to lunch, etc, is a good way to find them in your locale. Its not too hard: "Hey, boss, I'd like to get to know you better. How about we have lunch together sometime?")
I think it's better to "fish" for your fellow techies (rather than potential executives) for a couple of reasons:
1. You're likely to learn more (at least about your craft) in casual users' group meetings than you are in a business lunch
2. Good programmers and meetup organizers have a tendency to become the next business cycle's project managers and CIOs, so having a network made up of them is a great way to improve your chances at snagging your next great job
Also, in my experience at least, good managers are usually much more pro-active about getting to know their reports than the reverse. Regardless, it's not a very effective means of expanding your professional network, since your boss already knows you from your work together, and is unlikely to recommend you more or less enthusiastically because you sat down for a club sandwich together.
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You can always come to Hackers and Founders if you're in the Bay Area. We have a Meetup coming up on the 13th. http://www.hackersandfounders.com/
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If I think back on every significant business deal or job I've landed in my career, it's happened as a direct or indirect result of me putting myself out there and meeting new people.
More often than not great things are not going to just fall into your lap while you're sitting at home. You've got to get out there and interact with real live people to make things happen, scary as it may seem sometimes.
I've observed my naturally social friends (some of whom can go up to a group solo and initiate conversations) and I have come to the conclusion that it is a combination of (1) pattern recognition and (2) confidence. (1) - They have done it so many times they don't consciously grok about what they are doing, letting them be more truly aware/in the moment. (2) - In Daniel Goelman's "Emotional Intelligence" he cites studies where if you are nervous you can make someone else feel your nervousness/unease and make them feel uneasy (because their brain is empathizing at a sub-conscious level). Bonus observation - the universe rewards boldness.
As always, easier to read than to do.
I'd like to share a bonus tip from a master conversationalist/networker I met:
If you find yourself stuck with another solo person in a lagging interaction/conversation - do not shake hands and say "it was nice to talk to you. See ya" Instead state your intention and let them make a choice: "I'd like to talk to that group starboard. Come with me" This is powerful because you are taking the lead - and people always will appreciate leadership. If they do not want to continue hanging out with you, you've given them a graceful exit stage-right.
Not all geeks are shy (even though the author seems to think so). Still, these tips can be useful for everybody who wants to improve his/her networking skills.
Write well about topics you want to be considered an expert on. If you don't have a site or blog about this, you should probably reconsider that.
Business cards -- probably the single best place to invest $20 in your future. (If you desire to do work in Japan, drop what you are doing right now and get these if you don't have them.)
Ask questions, share code, give an unrehearsed five-minute lightning talk, whatever. Just make sure that people have a chance to notice you, and see you doing something interesting. If you make a habit of doing this, you will start developing a professional network, and opportunities will get sent your way.