Load your site in software like Scrapebox (for blog commenting), GSA search engine ranker (support multiple platforms) or GScraper (blog commenting) and run it in link building module. That's called spam.
1. Keyword stuffing (push in too many of those keywords in large quantities in a single page.
2. Spinning of articles (mostly Gray hat these days )
3. white content on white page (basically changing the font color)
4. Creating Copied content from high ranking sites(in hopes of getting ranked for the same keywords ).