How to increase keyword density?

[seopath]

hello folks,

I'm new to seo and working on one website after submission of it in directory and socila media only less page were cached by google but i don't know what to do further? One of my freind told me to increase keyword density but i don't know how to do it?

Here anyone know how to increase keyword density? and What is the use of keyword density and what the role it plays in seo?

Thanks.