On-page SEO optimization refers to the practice of optimizing individual web pages in order to rank higher in search engine results and earn more relevant traffic. This includes optimizing elements such as content, HTML source code, images, and other elements on a page that search engines consider when crawling and indexing websites.

Here are some key on-page SEO elements to optimize:

1. Title tag: This is the title of the web page that appears in the search engine results. It should be concise, descriptive, and include the primary keyword.

2. Meta description: This is a short summary of the web page that appears in the search engine results. It should also be descriptive, contain the primary keyword, and entice users to click through to the page.

3. Header tags: These are the headings and subheadings that organize the content on the page. They should be used in a logical hierarchy and contain the primary keyword where appropriate.

4. Content: This is the text, images, and videos that appear on the page. It should be high-quality, relevant, and contain the primary keyword and related keywords.

5. URL structure: The URL should be concise, descriptive, and contain the primary keyword. Avoid using special characters or numbers in the URL.

6. Internal linking: This is the practice of linking to other relevant pages on the website. It helps to improve the user experience and also helps search engines understand the structure and hierarchy of the website.

7. Image optimization: Images should be optimized for size and speed, and also contain alt tags that describe the image using relevant keywords.

By optimizing these elements on a web page, you can improve its relevance and visibility in search engine results. It's important to note that on-page SEO is just one part of a comprehensive SEO strategy, which should also include off-page optimization tactics such as link building and social media marketing.