I'm not expecting $400 for life, I'm more interested in trading time for money. How much time? Theoretically that should depend on how good I am.

Some of the opportunities people (such as patio11) have posted are what I'm interested in. I will be following up on some of those.

On the other hand, I also find some of the longer-term infrastructure-building advice (e.g. SEO, e-book stuff) useful, provided it's got a high probability of generating some cash within a month or two.