is ask them for references (=sites they made). Then have a look at those sites. Which ones do you like most? There might be design companies that have both sites you like and sites you don't like. Discuss those with them. They should be able to defend their design decisions.
Once you've got a shortlist, go and talk with their customers.
The big advantage of choosing a website designer: all information about their products and customers is available.
Kees
I have talked to dozens of web design companies concerning my companies website. How do I determine which ones will deliver a top a rated website? Has anyone heard of WSI?

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