Keywords are the words and phrases people actually type into search engines, and effective SEO writing starts by researching what an audience searches for and weaving those terms naturally into the content. Writers directly influence several on-page SEO elements: the title tag, the meta description, header tags (H1, H2), internal links to related content, and descriptive alt text on images. Older SEO advice encouraged repeating keywords as often as possible, but modern search engines prioritize genuinely useful, well-organized content for readers -- unnatural keyword stuffing today tends to hurt both readability and rankings rather than help them.