There seems to be a large focus solely on optimising pages with keyword rich titles and content. Remember that your site is for humans. It is far more important to get lower traffic with higher conversions than high traffic at the cost of poor user experience.

Before doing any SEO or PPC advertising you should make sure that your site converts. Of course you will need some traffic before you can test your site's ability to convert so you can try a small budget for advertising and some general SEO to generate enough traffic to test against.

Once you have improved your conversions you can then progress to more off site optimisations with the confidence that your work and advertising spend will pay off.