AMP (Accelerated Mobile Pages) are website pages that load very fast on mobile devices. In essence, they are a stripped-down form of HTML. These days Google cares a lot about how optimized is your website for mobile devices and apply penalties for those that are not compliant.
It's like an extended version of Google PageSpeed. Beside tips and tricks about the loading speed of your website, it also shows you some tips about the content, what focused keywords are you using, if your page metadata is correct for SEO and many more.
Check backlinks for your websites. If you have 0 backlinks than your website definitely will not have a good rank.
If you are going to build an ad with Google AdWords then you need good keywords. This is the right tool to find the right keywords.
Sitemap.xml will point Google Bots to crawl your website. Crawling it's an expensive operation, and helping crawlers to find the information it's an advantage. Afterall why Google should consume servers energy to extrat the right information from your website?