How do you successfully build an audience? Posting to reddit and HN is nice and all, but one or two popular posts rarely builds a ton of repeat users in my experience.
Just keep writing. Don't worry about building an audience, focus on improving your own writing ability and finding your voice. I wouldn't even really say I have much of an audience - but it has grown from only co-workers and friends to local developers to occasional HN/Reddit success.
When you think about bloggers that have a real, influential audience (PG, Joel Spolsky, etc) just remember how many years and hundreds (or thousands) of posts they've written.
I write a technical blog so people only really come to my articles when they are looking for a solution to a problem. Until recently I did zero "audience building" and had about 80% new visitors with 500 visitors a day.
I just wrote articles to improve my writing skills and now people find them in Google.
Reddit and HN (and DZone) can be seeds for other things - e.g. there are a bunch of email newsletters that pull content from there. I've had good luck with some of the programming language based subreddits, because they have a decent size audience but don't always have a lot of content. Usually there are big Google Plus groups of similar size.
Twitter is useful, because you can contact people directly (e.g. people like it when you write something using a tool they built). It's also a good way to connect with people at conferences because there is often a conference hashtag - I met a few people writing up summaries of talks. It seems like a lot of people use it as an RSS substitute as well, so it's a light-weight way for them to follow you.
Make it easy for people to discover when you post again. This could be anything from a mailing list (overkill IMO) or providing an RSS feed of your blog for people to subscribe to.
