The best way to promote your website is through social media sites such as Facebook, Google+, Twitter, LinkedIn and Pinterest. Create a business page and communities and post new car model pictures along with some quality information and its link on these social sites. Invite your friends and other members. Engage with them, answers every question that users left in your comment box. You can also start discussion in communities with your friends.
Along with this do Off-page SEO techniques such as forums posting related to your niche and on high PR websites, post high quality and unique articles on article submission, guest posting and press releases websites, also create a blog for your website and post free quality articles on it. This will definitely help you to improve website ranking in search engine results. All these Off-page SEO techniques must be done strategically and not in excess. Try to build your backlinks on high PR and domain authority website.
You have also have an eye on your competitors and check from where there are getting good backlinks. Build your link on that websites.