Navigation links matter in Automotive SEO, if possible link to your home page using your most important key phrase. This makes every page on your site 'vote' for the home page's relevance for that phrase.
Having an instance in your key phrase in bold type can help but try not to abuse. Bold the term or phrase once at most and more only if it makes sense in context.
Google employs a rational surfer model when valuing links. If a link is placed where an interested visitor is more likely to click, the link will get more value versus links stuffed in the footer of your site. This means, keyphrase relevant, in-paragraph links are important for auto seo. In general try to avoid more than 1 per paragraph.
Images should have fully descriptive ALT attributes and file names. That means the ALT attribute, written on a blank sheet of paper and shown to a stranger should explain what they'll see. In addition, the caption proceeding the image should also describe the image.
Avoid using nofollow for links within your web site. It does not 'sculpt' pagerank: it makes it disappear. Only use nofollow where search engines might think you're selling links to external sites.
Under the Hood
The title tag is the single most important element in on page SEO. Make sure your key phrase comes first, but also make sure the title tag is well written and would make people want to click, because it will shop up in search results.
The description meta tag won't influence rankings, but may show up inas the search 'snippet'in search results, so write a good one that will make people want to click. The keywords meta tag doesn't matter at all since seach engines ignore it.
Good semantic markup will make your page easier to maintain, cleaner, and faster-loading. Some in the industry argue it doesn't help Automotive SEO, I would definetly use