Do seo optimization - how?

the on-page list is right, but check the boring stuff before any of it. put the site in Search Console and look at the Pages report - if google hasn't indexed a page, no amount of title tweaking helps. make sure a sitemap is submitted and nothing important is blocked in robots.txt. people lose months to that one.

Start page by page. For each one: main keyword near the front of the title tag, one clear H1, a short readable URL, a meta description written to get the click (it doesn't affect ranking directly), alt text on images, and a few internal links to and from related pages. Then the part people skip - read the page and ask if it actually answers what the searcher wanted better than what's already on page one. That matters more than all the tags put together.