Here are some top tips for blogging from Paul Bradshaw of online journalism blog. I read the piece and decided to take the first piece of advice which is to respond to something elsewhere on the web. The other ideas for gaining visibility are as follows:
suggest an idea
interview someone (i've not done that yet)
blog an event (yes, done that)
ask a question (?)
pick a fight (should do)
reflect on something (do too much of that)
do something visual (now you're talking)
review something (like this list)
make a list (indeed)
write a how to
let someone else post
on the how to suggestion they note that - one of the most popular types of search query is ‘How do I..?’ or ‘Why do..?
For a more in-depth explanation here's a link to online journalism blog (if indeed you agree that blogging = journalism) and he's looking for more suggestions.