We have recently updated our site: http://toyota-dealer.org. The site uses a template so there are limitations on how much design can be changed. What keeps us awake at night is SEO.
As an intro: We are a car dealer who export luxury cars, pickup trucks, Sport Utility Vehicles, Multi-Purpose Vehicles, ambulances, anti-terrorism vehicles, armored cars, vans, trucks, buses and construction machinery from Thailand, Australia, United Kingdom, USA, Japan, Singapore and Dubai UAE. Since we export hundreds of different models, it is hard to optimize the site for so many different keywords without sounding spammy. But the issue is that if we don't tell our customers that we do sell these vehicles neither Google bring them to us nor will they know if they visited the pages.
SEO is our major concern as Google recently has been cranky will all the weekly and monthly updates it is spewing out, there is a queasy feeling in the stomach all the time with the see-saw we experience with the sites.
Four car models that sell well are Toyota Hilux Vigo, Toyota Fortuner, Toyota Prado and Toyota Land Cruiser but it may be because we have optimized the site for these keywords. I sometime get the feeling that we may not be getting customers for other vehicles because we are nowhere on Google for them.