There is a lot to answer for here but I can give you some basic tips.
You should pick out your target keywords and then select which pages you will optimize for those phrases. Make sure you place them in all relevant areas of the page (i.e. title tag, meta description, headings and copy). Remember, only one keyword and its variants per page.
Build links to the site. You could do this by creating content that is sharable like an infographic. You could also reach out to other website owners and talk to them about guest posting on their sites. There are also tons of other backlink strategies.
Here is also a pretty good checklist for what to do,
Hope that helps,