Get people's attention!

Getting people to read your blog, social status update or any other content really (including emails and memos) comes down to relevance and interest. A good subject or headline is the first step. Here are some types and examples that resonate:

How to

People with problems and challenges want content that solve them. The words "How To" identify your content as instructional. Be sure to include some key words that relate to issue you're addressing. #HowTo is a popular hashtag you can leverage, too.
Example: How to write better news release quotes

Contrary PoV

Sometimes the best way to engage the audience is to shock them into attention with a contrary point of view. Whether you're busting a myth or simply staking out divergent ground, this tactic can be effective.
Example: PR & social media aren't free
Example: National write a business plan month? Not!

Tips/Advice

Like how tos, advice/tips is also a popular content category and, thus, an effective headline strategy. Using "tips" or "advice" in your headline/subject may attract people who are looking for guidance and consulting input. These, too, are oft-used hashtags; some industries or topics have their own tags like #ProPRTips and #datingadvice
Example: Tips for corporate gift-giving
Example: Financial advice for freelancers/contactors

Questions

We want answers and using questions in headlines and subjects helps us find them. This also is a helpful headline for web content, since many people search using questions. Queries also pique interest, luring in people who want to know more.
Example: What is plain language?
Example: Wondering how to avoid a major social media fail?

Cautions

Nobody likes making mistakes, so the cautionary tale headline or subject can be very successful. Based on my own analytics, any post with a head including "fail" or "don't be this guy/gal" gets lots of reads.
Example: Auto-tweet fail
Example: Don't be this guy

Additional tips for writing headlines/subject lines

It's also helpful to include numbers. Personally, I like smaller quantities like "2 tips for creating more quality content". I recently got a blog post from a trusted source, but the title read "101 ways to..." and I didn't even open it. I didn't feel like I had the time. But if you want to display domain expertise, that might be a good tactic for you. Fans of High Fidelity like me love the top 5 list. Letterman fans engage with the top 10.

Sometimes you can hook your subject or headline to a news event, trend or celebrity. For instance, I ran a series of posts for Global Entrepreneurship Week, and traffic picked up -- most likely from people following the #GEW hashtag and searching for information on the event. But you want to be careful linking your content to news and celebrities lest you look like you're news-jacking or you turn off your audience because they don't get or like the association. Here's some advice on how to peg content to news and trends.

Good luck!