1. Use a single domain or subdomain when possible
2. Use human-readable URLs
3. Use keywords in URLs
4. Canonicalize URL’s serving the same content
5. Exclude dynamic parameters when possible
6. Use shorter (versus longer) URLs
7. Match URLs to titles most of the time
8. Omit stop words when it improves readability
9. Remove or control for unwieldy punctuation characters
10. Limit redirection hops to two or fewer
11. Limit folder depth
12. Avoid hashes in URLs that create different content
13. Avoid case sensitivity issues with redirection and canonicalization
14. Use hyphens or underscores as preferred word separators
15. Avoid keyword stuffing and repetition
Something else (share it with us in a post)