If you have relavent, compelling content for a high volume google query then by all means optimize for it.  But remember that 20% of the queries Google receives each day are ones they haven't seen in at least 90 days (http://support.google.com/adwords/answer/2497828?hl=en) so don't be afraid to anticipate a future audience, even if the traffic isn't already in Google Keyword Tool.

Obviously, there are industries (news and trend based) that are perpetually in the cycle of creating, anticipating, or quickly reacting to new keyword spikes.

Either approach is valid, but I suggest you let your content and your passion for your audience be your guide.  If you produce great content, and you are confident their is an audience that wants to consume it, then don't let the lack of keyword traffic stop you.  The world just doesn't know they need your keyword yet!

Good luck,

-Jason

The debate about subdomains vs. subdirectories has been going on for a long time.  You have to be careful about reading old stuff, because the best answer has changed over time based on changes to search algorithms.

I.E.  There was a time when "link-juice" was treated separately on each sub-domain, so subdomains could dilute your effort.  There was also an era, when Google would allow a max of two results per sub-domain on a SERP, and so people would use multiple sub-domains to get the potential for more links on a SERP.

At the moment, they appear to be roughly equivalent   And so the decision usually comes down to other convenience issues rather than SEO benefit   In your case, since you're already on a sub-domain I probably wouldn't bother to move them and do all the re-directs, ect...

I'm basing this advice, largely on Matt Cutts video answer here:

https://www.youtube.com/watch?feature=player_embedded&v=_MswMYk05tk

watch?feature=player_embedded&v=_MswMYk05tk

At the moment, structured markup doesn't effect your SEO directly.  Rather it improves the likelihood of your search results getting rich snippets  which would then have higher click through rates.

Schema.org features a large variety in it's hierarchy  so odds are that some of your articles fit in it's taxonomy:

http://schema.org/docs/full.html

The trick is finding someone that covers your sector.

If it's an e-com site, the Internet Retailer Top 500 is popular and a newer list from website magazine:

https://www.internetretailer.com/top500/

http://www.websitemagazine.com/web100/2013/

There are a variety of comercial services:

Compete.com

alexa.com

comscore.com

Many vendors work with a large number of sites and get access to their analytics, and it's not uncommon for them to publish aggregate benchmarks from their client bases:

http://www.rimmkaufman.com/thought-leadership/quarterly-reports/

http://monetate.com/research/#axzz2MP5G0Wug