Search Engine Optimization, or SEO, is the practice of increasing a website's organic (non-paid) visibility and traffic from search engines. SEO is generally divided into three main types. On-page SEO focuses on optimizing individual pages' content and HTML elements to rank higher and earn relevant traffic, including elements like the title tag (the clickable headline shown in search results), the meta description (a brief page summary), the H1 tag (the main heading indicating the page's primary topic), and internal linking between pages to distribute authority and aid navigation.
Off-page SEO builds a site's authority and trust through external signals, most importantly backlinks, which are links from other websites pointing to your site that act as votes of confidence. The clickable portion of a link is called anchor text, and search engines consider both the quantity and quality of these signals. Domain authority is a relative, conceptual measure of a site's perceived strength and ability to rank based on links and other signals. Technical SEO improves the underlying infrastructure of a website so that search engines can access and understand it, including crawlability, indexation, speed, and structure. Important technical elements include the sitemap (a file listing important pages to help crawlers), the robots.txt file (which controls which areas crawlers can access), and the robots meta tag, which can include directives like noindex (to exclude a page from the index) or nofollow (to prevent passing ranking value through a link).
Keyword research is the foundation of SEO, the process of finding and analyzing search terms to target in content. Marketers evaluate search volume (the average number of searches per period) and keyword difficulty (an estimate of how hard it is to rank). Keywords are categorized by length, with short-tail keywords being broad, high-volume, and highly competitive, and long-tail keywords being more specific and usually easier to rank for. They are also categorized by keyword intent, the underlying goal of the searcher, which can be informational, navigational, transactional, or commercial. Other technical considerations include mobile-first indexing (Google primarily using the mobile version of a site for ranking), page speed (which affects both user experience and rankings), Core Web Vitals (user-centric performance metrics for loading, interactivity, and visual stability), and crawl budget (the number of pages a bot is willing to crawl in a given time).
Local SEO focuses on optimizing a business's online presence to appear in local searches and map results. Key practices include maintaining a Google Business Profile, ensuring NAP consistency (identical Name, Address, and Phone number across all listings), building local citations on directories, generating customer reviews, and using appointment scheduling integrations. For international sites, the hreflang attribute signals language and regional targeting, while schema markup (structured data) helps search engines understand content types and enables rich results like star ratings and FAQs. On the results page itself, the SERP (Search Engine Results Page) may now include a featured snippet, a highlighted answer box, or simply serve a zero-click search where the user gets their answer without clicking any result. Tools like Google Search Console help monitor search performance, index coverage, and technical issues.