The secret is Whales. Since you can get an upvote which worth more than 100 other minnow votes... (in rewards i mean)
So you should get whales upvote, but you cant force them to vote for you or to spam them with useless content or non-targeted ones. Because most people try to do it and its annoying for them.

Building network is the key yes. You should build an audiance according to your topics and also promote your content. People just start to understand that there s no magic in here, good content is never enough by itself, it needs promotion and networking, as well as.. Luck :)
So good luck to you @stephmckenzie :)

ps: by the way you did more than thousand dollars in a month posting on Steemit ;) i do think you're in the lucky ones ;)