1. All the pages should have header1(H1) and optional header2 (H2) tags.
2. SEO friendly url is a must
3. All your pictures/images should have SEO friendly names.
4. Robots.txt are found.
5. Do away with inline css and java-scripts.
6. Your domain should be added to Google Webmaster Tools and Bing Webmaster tools.
7. Google Analytic should be installed.
8. Install an SSL certificate if you don't have one.
9. Your website should be loaded fast.
10. If your website is for wide audience use CDN to speed up them it may increase the speed a lot.
11. Your content should be written for people not for bot, it should be unique and valuable.
12. Meta Title characters should be between 50-60 .

Source: http://9jayes..com/2016/11/what-you-have-to-do-prior-to-launching.html?m=1

Nice tips