Shopify store -- 2

I have a shopify website that i need help with. Looking for assistance on where to start on improving site. Ive been told many different things on where to start. Id like someone to look at the site and let me know everything that has to be done in order to be a high ranking site.. from the first step to the last.. what has to be done? Also need the site to be optimized for speed and the SEO done.