Keyword Stuffing
refers to the practice of loading a webpage with keywords in an attempt to manipulate a site’s ranking in Google’s search results. Filling pages with keywords results in a negative user experience, and can harm your site’s ranking. Focus on creating useful, information-rich content that uses keywords appropriately and in context. (Google)
The best way is, first you Google out the best tools for Keywords Suggestions and Keyword Research on the internet. I recommend “IBP and Arelis”. Its the best SEO tool a webmaster should have. Search for websites in your niche, compare them with this tool and check what keywords, meta tags they are using and what do u think will be the best among them.
Adding keywords that are not related to the content of the webpage, Repeating keywords, or adding anonymous keywords and hidding them under some image through css or blend them with the background color is also called Keyword Stuffing. Google hates that !
