There’s no shame in self promotion
I don’t think there is such thing as shameless self promotion. It’s a part of doing business. You have to believe in your product and you have to advertise it as much as you can without getting annoying. If you don’t believe in yourself, nobody will.
There’s also a gain in promoting the work of others. As Zeldman puts it:
But direct self-promotion is ineffective and will go unnoticed unless it is backed by a more indirect (and more valuable) form of marketing: namely, sharing information and promoting others.
Is your Twitter feed mostly about your own work, or do you mainly link to interesting work by others? Link blogs with occasional opinions (or occasional techniques, or both) get read. The more you find and promote other people’s good work, the more in-the-know and “expert” you are perceived to be—and the more you (or your brand, if you must) are liked.