If I'm merely setting up an appointment, I don't bill for that call. If it is only 5 minutes, I don't bill for it.

Everything else should be billable or I'm wasting my own time (and probably my client's time as well).

I'm either:
having an initial needs conversation with a client (up to an hour and not billable)
having needs conversations about projects with a client (requirements gathering or analysis, all billable)
doing the work (solving problems, making recommendations, writing up results etc. all billable)
providing a conclusion (same as the one above)
sending out invoices (not billable of course)
everything else I do... blogging, standardizing things so I can re-sell them etc. is all on my time b/c it's product development or marketing.

If I'm not doing something that falls into the above issues, then I'm either losing money or wasting time. The one exception is when I am fixing something that was a fixed price and already paid for... then it's losing me money. I try to avoid fixed prices when possible.

I also keep a lower than market rate because a lot of my work is not well defined at the outset and I spend a lot of time helping my clients figure out "what needs to be done."