Sitemaps are a tool for Search Engines, not for users. Also, not having sitemap isn’t an issue.
SEO Tip: Plenty of Content, but not too much
Make sure you have plenty of content for your visitors to read; it’s for your visitors — after all.
SEO Tip: Go Social & Use Knowledge Graph
Search Engines don’t just look at your website anymore these days, but also take a look at social activity.
SEO Tip: Descriptions are organic & Limiting scripts
Every little detail on your website can help out with SEO, e.g. reducing your website’s size helps a lot.
SEO Tip: Domain Age is Important.
With SEO, the domain age is very important. The older the domain is, the more trust it most likely has.