Lorel - 12:52 am on May 29, 2010 (gmt 0)
I manage about 50 sites I have designed or redesigned and none of them have lost a major portion of their traffic. They may be down 10% at the most but that's about all. Most of them would be considered small sites under 100 pages but at least 1 is over 4,000 pages. Maybe if I explain what I have, or have not, done it will help someone.
First off, I follow the Google guidelines to the point of being obcessive, i.e., no buying links, no triangular linking, no blog rolls, I don't even trade links on 90% of the sites I manage.
I always encourage clients to add content that people want to link to on their own and to also participate in forums, blogs, set up a twitter account or facebook, and other social marketing to draw traffic, if not links. And lately since the new Google Layout to add videos so they have a chance of ranking if people stray off into the left side bar.
When designing sites I make sure the clients focus on 2-3 word phrases and interlink those words from within their content to their other pages.
I also take special care with canonical fixes, avoiding duplicate content and too empty pages. And I insist they add a couple paragraphs of unique content to each product page and have more than one page focusing on a product and I keep those pages linked from, and close to, the home (not buried within folders).
Not all of my clients take action on my advice but those that do are doing ok even in this bad economy. One of them said he's had his best year ever, this last year, even with this bad economy.
My own site is so busy I turn down a couple jobs per week and I'm constantly on the verge of burnout (don't have time to read WebmasterWorld much anymore) and I don't even focus on my main keywords. I provide info (articles and tutorials) that helps other website owners and that draws in enough work to keep me busy and I don't have to go searching for links either.
Basically I follow what Matt and Vanessa have been preaching for years.