I know this question gets asked a lot because I've asked it myself. The answer is usually do a search.
The problem with doing a search on the WP forums is that only either the last 15 recent posts come up, the second option posts that are supposed to be relevant, are never that relevant. Terms like "Self Promotion" are thrown around all the time in forum posts which makes a Google search of the forum impossible as too many results come back.
Most of the support documents and those you find searching on Google for tips on publicising your blog, just regurgitate the same information. Suggesting you connect to FaceBook and Twitter etc, and post on forums relevant to your subject.
Someone mentioned 2leep to me in another thread. I've submitted a few posts to them. Some accepted some rejected. It's brought a few hits back. Nothing amazing, I've looked at more posts than anything.