If you're using guest blogging as a way to gain links in 2014, you should probably stop. Why? Because over time it's become a more and more spammy practice, and if you're doing a lot of guest blogging then you're hanging out with really bad company.
Matt's blog post. In it, he also has this to say:
"Ultimately, this is why we can't have nice things in the SEO space: a trend starts out as authentic. Then more and more people pile on until only the barest trace of legitimate behavior remains. We've reached the point in the downward spiral where people are hawking "guest post outsourcing" and writing articles about "how to automate guest blogging.
"So stick a fork in it: guest blogging is done; it's just gotten too spammy. In general I wouldn't recommend accepting a guest blog post unless you are willing to vouch for someone personally or know them well. Likewise, I wouldn't recommend relying on guest posting, guest blogging sites, or guest blogging SEO as a linkbuilding strategy."
Purpose of Guest posts:
As with anything, you don't want to be out there trying willy-nilly to get your posts on every blog for the sole purpose of building (probably bad) links. It's important to have this tied to your business and marketing goals, as you would with any other tactic. SEO is only one piece of the larger strategy, and if you focus solely on writing posts for link building purposes, you're missing out on a ton of other possibilities, such as:
Branding, branding, branding
Build credibility in a specific niche
Exposure to new audiences
Authorship: The more legitimate posts you write and connect to your Google+ account, the more likely your lovely face will show up in the SERPs.
How to be a better guest poster:
Develop a relationship with the publisher outside of "guest blogging platforms" in order to customize the relationship better.
Pitch a series of content instead of one "guest post".
Describe yourself as an "expert contributor" not a "guest author", explain the difference if you have to, and explain to the publisher why this is better for their site.
Don't contribute to sites that want to publish your content under a general "guest author" account. Always insist on your own contributor/author account, and markup with rel author.
Work with authors who have Google profiles to which they can add contributor to links. If they don't have one, help them get one.
Go back to the same authors for similar content to develop them as experts in a specific niche (e.g. if John Smith did an article for a client on PBX solutions and you have need for another piece of content about VOIP, office phone systems, etc... go back to John Smith again)
If the resident authors don't have their bio below/above every post then our content shouldn't have one either.
Stop thinking about links. Think about traffic and exposure instead. Links are fine if they are relevant, but don't let a nofollow policy keep you from contributing to a major site with lots of traffic in the clients' niche.
Track the right metrics, which starts with aligning our goals with the clients'.