How should you evaluate SEO firms? Well, most people start by searching Google for SEO. This is certainly not a bad idea. Those SEO firms with the best skills will be able to take their own medicine and help themselves achieve a page 1 placement. At Semify, we've done this on the term SEO technology. In other words, we've used our own SEO technology to help us become a page 1 listing in Google on the term SEO technology.
The only flaw with searching for SEO firms this way is that you will be getting the more expensive ones. If you are looking for affordable SEO or for cheap SEO, they are not likely to be on page 1 of Google for such a competitive term. Why? Well, it's just like you are not likely to see a discount seller running an ad during the Super Bowl (okay, there are some crazy exceptions to this - especially during the dot com craziness). You get it. Discount SEO firms will not be able to afford the Super Bowl ad, or the efforts it will take to be on page 1 for the term SEO.
So how do you find the right firm for you? Well, the best possible way is to ask people who have worked with an SEO. The personal reference simply can't be beat. Using this method, there is already a relationship established somewhere which implies some level of trust. And trust is the name of the game in most of business - especially when looking at search engine optimization companies.
But in the absence of that, there are other tricks. Look at the client list. Make sure there are some Fortune 100 clients on there that you recognize. Big companies have the time and budget to do the due-diligence you can't do. They run firms through the ringer as they are selected to make sure they will perform after the contract is signed. Usually, SEO firms with big corporate clients indicates that you can trust them to bring you good results. Not always true, but usually a good indicator.
Finally, be sure to ask tons of questions as you get to know the firm. At Semify, we like to give every single new potential customer an in-depth demonstration of our SEO technology prior to signing up. This way they know exactly what they will get and how they will see their progress and monitor our services. We find this is a critical step for even the smallest client.