Big Mistake most blogs make -- Seth Godin
"The mistake most blogs and books make: they are about the writer, not the reader," says Seth Godin.
It's about the reader, not you. Offer value.
With each post, think "how does this add value to the reader?"
OK, maybe you can occasionally be self indulgent and have a self serving post, occasionally.
Maybe your readers will even like it, because quite honestly you don't know what readers will like, what they resonate with, what they'll groove on, what they will value, but you better have a good idea!
Blogs -- they're not about you.