5. No social signals.
As the influence of social media has grown, one of the signals today's search engines clearly seem to measure is your following on the various platforms, such as Google+, Facebook and Twitter.
Lacking a presence here not only dings your online reputation, you miss out on the conversation and the potential to stimulate referrals. Being unsociable tends to isolate the practice and sends one more signal to prospective new patients that you're not keeping up.
Make sure your social media branding matches the look and feel of your website, which should serve as the hub of all your online marketing channels.