How do I create an SEO-friendly URL structure?

Good URLs are short, descriptive, and hierarchical. Rules: 1) Use lowercase — /blog/seo-guide not /Blog/SEO-Guide. 2) Use hyphens — /custom-website-cost not /custom_website_cost or /customwebsitecost. 3) Keep it short — /blog/seo-guide not /blog/2026/05/the-complete-guide-to-search-engine-optimization-for-beginners. 4) Include the target keyword — /services/web-development not /services/service-1. 5) Use flat hierarchy — /blog/article-title not /blog/category/subcategory/date/article-title. Fewer slashes = better. 6) No IDs or parameters — /products/running-shoes not /products?id=4523&color=blue. Structure by content type: /blog/[slug] for articles, /services/[service] for services, /compare/[a-vs-b] for comparisons, /glossary/[term] for definitions. Never change URLs after publishing without 301 redirects. Every changed URL without a redirect loses accumulated search ranking and backlinks. Common mistakes: including dates in URLs (makes evergreen content look outdated), using category paths that change (breaking URLs when you reorganize), and making URLs too long (Google truncates after ~75 characters in search results).