The most common question I hear these days from any client is where to find experienced SEO folks. This is a difficult question to answer because, in almost every case, there are far more SEO jobs than there are candidates in the space. The most experienced SEO experts are either in top-level positions at an agency or have their own firms consulting for companies around the world.
Many of the large agencies worldwide have a large selection of employees at a very basic level, which makes up 95 percent of their staff, and a few key employees who really know what they're doing and have a ton of experience to back up their resumes. (This is also a key driver for many companies to move away from agencies and start working with an in-house team that they can manage at a better level.) Thus, the best place to look for new people is usually the five percent who are ready to move on and get to the next step in their careers.
The majority of this small niche group commonly had no experience in the SEO space before working for these agencies and learned at the expense of the agency's customers. The best people I've hired over the years learned their traits from hands-on experience and were able to gain an advanced understanding by experimenting over and over again.
Throw everything you know about hiring out the window before starting this process! Don't look at education! I can't tell you how many good people you'll lose if you're looking for a bachelor's and/or master's in a specific area. There aren't any educational tracks in any school anywhere around the world that can prepare you for this job.
My apologies to any school that thinks they can teach this and get anyone ready for the real world. Even the most technical school is between three and six years behind the current and real world examples of what's going on.
There are a few simple things to look for when scanning through resumes. Look at the companies that this candidate has worked with before. Are they large in size? Do you know who they are? Be sure that you can tell if they have actually done anything to improve their "rankings" or what I like to measure by "traffic" increases.
If the resume can't hit these areas, it's likely that they aren't experienced at writing a resume, so you may have to ask them in a phone interview about these parts. A poor resume is usually a good indicator of poor management skills in general, so this should be taken into account. However, if you're looking for an analyst-level person, this really could be overlooked.
During the interview process, there's only one word that I look for when talking with a candidate to work on a large site: SCALE. If they don't plan an SEO strategy around scale, they should not be working on a site.
If you hear anything about changing keywords or titles of a "single" page one by one, move on. It's obvious they've never set up a site to grow at a large-scale. This level of optimization is learned by experience and is extremely important for any large site with over 100,000 pages. Normally, I'm recruiting for staff with sites of at least 1 million pages at the small side to more than 100 million pages.
Searching for a high-level SEO candidate is going to take time and effort, and ultimately lead to much frustration. If you identify the key traits you're looking for, and what you're willing to compromise on, your search will go easier.