I live in DC, and I can have access to key people. I am clear what is my goal for this next decade. I want to build and maintain a professional network in DC and in my original country. I don't want to just knock doors. I want to strategically know the people to reach, what is the WIFIIT for each network group, and how to maintain the network.
The best advice about networking is to show up. And not just once. Keep going.
Sounds really obvious but if you are a comfortable "old shoe" around groups you need to mingle with for business you'll have little trouble talking business at appropriate moments.
This is why more business is done at golf clubs and other hobby locations than in many boardrooms. If you're always around in a good way, and share a common goal or interest in that situation you will become more credible, more trustworthy and thus more likely to do business with.
The real trick though is you have to be genuine. Faking a like of golf and taking three lessons will not work in the case of golf or any other hobby or interest, whatever it may be.
Good networking is about farming not hunting. Try to find people who are also above your own level - more successful, more stable and more helpful. That will have the effect of raising you over time without you even realising it.