Search engine optimization (SEO) has a bit of a Jekyll-and-Hyde personality. It can be a tremendous boon when it works well, but when it goes wrong it can easily turn an otherwise sane person quite mad.

Those who hunt the SEO grail do so for a common reason: Organic search continues to offer a powerful channel for attracting online visitors without a major advertising budget, a chance many small and midsize businesses (SMBs) cannot afford to ignore.

"It's still a very high return on investment for those who are willing to be both creative and be appropriately technical," said Rand Fishkin, CEO of SEOmoz, in an interview. "I think the wonderful thing about SEO for SMBs is the opportunity is continually increasing, and that's because the quantity of searches and searchers continues to grow."

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But SEO is not an easy game. Even once you think you've got it figured out, a minor change in an algorithm or the competitive landscape can banish yesterday's page-one result to tomorrow's search oblivion. Fishkin, who wrote the book on SEO--or at least one of them--shared his current best practices for SMBs, including advice on how to handle negative changes in your results.

1. SEO means different things to different people.

For some SMBs, SEO simply translates to: Where do I show up on Google? A more comprehensive view of search would at least need to include Microsoft's combined Bing-Yahoo platform. These days, Fishkin said, plenty of folks use SEO to mean a variety of things that extend past the core definition.

"The last six to twelve months, we're feeling a different thing, where SEO is coming to mean all of inbound marketing for some people," Fishkin said. He's something of a purist, noting that although the acronym stands for search engine optimization, more and more people might use it interchangeably for Facebook, Pinterest, and other sources of online referrals. Consider it a reminder to know what matters to your business in terms of how people find it online. There's no one-size-fits-all strategy, particularly not in the diverse universe of SMBs. Know what it means to you and tailor your approach accordingly.

2. Mobile does not change everything.

You don't often see that sentiment these days, but Fishkin thinks the predicted sea changes in SEO as a result of smartphones and tablets are off-target. In his view, mobile is not revolutionizing search results; rather, it's increasing the volume of search results, which is a good thing for marketers.

"Your mobile phone is merely a small laptop," Fishkin said. The increasing use of responsive design--websites that adjust appropriately for the user's screen size, no matter their device--is one of the key reasons behind his opinion. "Mobile has actually become much less of a transformational technology and much more of an enabling technology. It merely means we are much more frequently connected to the Web."

3. Get the basics right.

The caveats are out of the way; now enter the fundamentals. "Make sure that your website is accessible and follows the key best practices for SEO," Fishkin said. Those include: Don't block robots from accessing your site's pages. Don't have URLs that produce duplicate content. Do keyword research for all of your online content development, including marketing, branding, product descriptions, blog posts--"whatever content you're producing on the Web," Fishkin said. "Those essentials are still absolutely critical to getting SEO right."

Here's your reason to do the grunt work, according to Fishkin: "Because so many people get them wrong, there's still a big opportunity for SMBs that take even those basic best practices seriously."