How do I fix duplicate content on my website?

Duplicate content usually means the same page is reachable at more than one address, which splits the signals between them:

• Pick one canonical address - www or bare domain, with or without a trailing slash, and redirect the rest to it.
• Set a canonical tag on each page pointing at that chosen address. 88% of Australian small business sites already do^*.
• Watch parameters - tracking and filter parameters create fresh URLs for identical content.

Fix it with redirects and canonicals rather than by deleting pages; the goal is to consolidate, not to remove.