What type of search do you do to get that results?

And what exactly are 'tags' ? The main blue title usually for Google is represented by title element in your pages

By the way, sitemaps effect are not immediate and as is stated by Google itself a sitemap affects very marginally the ranking in search results.

Here you find a complete list of all factors used by Google for ranking in searc results: http://backlinko.com/google-ranking-factors

The only thing you can do with sitemap, is indicate a higher priority to elements. This should help Google to understand what are the most important links on your site