There is a fine line between asking for consideration, for attention as part of a smart marketing campaign, and becoming annoying with pestering. I have been asked by an ex-colleague I trust and like to vote for his work in a survey for his piece on diesel emissions. This is fine by me because I know him and he had my attention anyways. But self-promotion is often not so clearcut.
I am of the belief that given a choice it is always preferable to let the work speak for itself. That way if you are good enough, others will take the time to knock on your door to find out what you do. You won’t have to bother anyone out of the blue.
Of course this is not the only method for selling something to someone, but it is probably the pinnacle I am trying to aim for.