Google uses a huge number of factors to determine your position in search results. Fortunately, your website has been built to cater for most of these factors and should achieve a good ranking but there are a few things you can do:
Every link from a website to your website is a referral, or a pat on the back. Google counts up the number of links to your website and uses that number when determining where to list your site in search results.
Google also looks at the text in a link and associates that with your site too. So a link that says my town name tyres is significantly better than a link that says click here.
UPDATE: Check our easy-to-implement VRN/size lookup script for the best possible inbound link available (with a conversion rate of almost double that of standard inbound links).
Google always likes to list websites that are fresh. By updating the content on your site, especially your home page, you will show Google that your site is current and loved.
Aim to change the content on the home page (news, special offers and promotions etc.) at least every month.
If you're a habitual Tweeter or a Facebook addict then you should promote your new website by creating tweets and wall updates that point to your new website.