The first step in an Audit it to make sure to know the keywords which are key to your business, which ones for which you are already ranking and those for which you are not, select the ones which are more likely to bring the best traffic depending on your site's strength: if your site is quite new, you may not want to target keywords which have great Search Volume but which are too competitive. Content of course is the most important, but you also need to include words your visitors use to search for your services, and welcome them with quality landing pages. Keep in mind you should produce content for users not just for SEO. Linking internally in an efficient way is also key for user experience and search engine bots.
Keeping an eye on indexation is extremely important so that you don't waste crawling credits. Avoid however duplicate content that would confuse search engine bots with poor indexation messages. Make sure also your mobile version loads fast. Make sure that your website uses https.
Once you are confident you have great content and a website you are proud of, you can with more confidence ask for quality links pointing to your website. Links are still key in SEO and more and more difficult to pro-actively collect if you are still new in your business. PR, social media, word of mouth and other media coverage increase visibility and more and more websites will starting linking to you naturally if you have a website which stands out from the competition. Before that happens, there are ways to get going while taking care of your brand image and expertise in your field.