Here are some blog posts that discuss how to deal with the changes with SEO...
Stop. Feel Like Your Marketing With a Blindfold On? Not Getting Results? Here's Help.
Did Google Kill The Niche Site Model?
100,000 Monthly Page Views and No Backlink Building
WordPress Posts vs. Pages and SEO
The bottom line is, any SEO strategy that can be easily duplicated by the owner to "fake their own popularity" (submitting their own links) is less and less useful and largely ignored by Google.
Gaining natural, relevant links (guest posting on relevant sites, etc.) is the best way to go from now on. Don't waste your time on linking schemes and chasing large quantities of backlinks. It's less about the quantity and more about the quality of links you gain.
Here are some great videos from Matt Cutts on SEO...
Why Do Paid Links Violate Google's Guidelines and Other Ads Don't?
How Does Google Consider Sitewide Backlinks for SEO?
What is Google's View on Guest Blogging For Links?
If I Haven't Been Participating in Link Schemes Do I Need to Worry About My Links?
Social media is now playing a bigger role than ever with SEO. So the more shares you receive from influencial people, the more SEO benefit the article will receive in the long run. Building authentic relationships with people in your niche is now more important than ever.
Start by engaging with people in your niche on Twitter, FB, Google Plus, etc. If you have a blog, join networks like BlogEngage, Triberr, Scoop.It, BizSugar and more.
Here are some articles on social media you may find useful...
How Ti Drives Traffic to Her Site Without Google and Her Advice to You
Get More Viral Traffic and Exposure From Pinterest
Understanding Google's Author Rank and How to Use It
If you're new to blogging and social media marketing (SMM), grab a copy of Kristi Hines' The Ultimate Blog Post Promotion Guide. Kristi is a social media marketing maven and the ebook contains many easy-to-follow strategies for people new to SMM.