In order to succeed in SEO, especially when talking about improving placement of websites on Google, adding quality contents to the websites and at the same time gathering good links will help. After launching your website, optimize your pages very well, use the right unique title plus descriptions tags and do not forget to publish some good content pages on your website for the audience.
One of the reasons why many websites, even the ones with lots of incoming links do not function satisfactorily on Google is because they lack quality contents. The next move would be building links which can act as online votes pointing to your pages. If you manage to gather some good links from relevant sources, their impacts on your ranks will be great, but you should be patient as well.