But don't stop there. Keep an eye on good quality blogs written by others so that you can share their latest updates. You'll get known as an expert not just by offering your own quality content, remember. This status will accrue if you consistently point your followers in the direction of excellent articles created by others, too.
You should also do searches for relevant news items on Google News and similar aggregation sites. There are always tons of interesting developments that are well worth sharing with your followers. Then there are the press releases themselves.
The great thing about these reports is that they are new, interesting, and specific. And they often contain keywords and phrases that you can use as hashtags. If you use a variety of these consistently you'll get found by a greater number of people, and grow a quality following more quickly.
I've been doing this consistently recently and it clearly helps a lot. When tweeting press releases for my Twitter account for this site, for example, I often include hashtags like #socialmedianews, #facebooknews, etc. So I always look for releases that are appropriate for this. There is certainly no lack of them.
If you have a geo-targeted site, tweeting local news items and press releases can be a really good tactic, too. You'll get the eye of people in your target area if you consistently do this. I've been doing that with one of my accounts related to my city, for example. It works well.