Ask HN: Self-employed - How do you keep a normal schedule?

Like I said in the title, I've recently left my full-time "regular corporate" job to go at it on my own as an iPhone developer, doing contract-work for small firms. Does the HN community have any advice for staying focused and keeping good work habits. Specific advice on not getting distracted (by HN, for example!) or how to manage your sleep schedule would also be appreciated.