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 just wrote articles to improve my writing skills and now people find them in Google.
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.