Start by comparing ranking URLs for the same keyword in Search Console; if they rotate or swap positions, that's a red flag. Look at drops where impressions stay steady but clicks split across similar pages. Logs of queries and landing pages act like heatmaps, showing internal competition instead of external penalties. Also check on-page overlap in titles and intent similarity. When cannibalization is confirmed, consolidating or differentiating pages usually restores clarity and rankings over time. Cross-check cannibalization by mapping keyword clusters to each URL and spotting overlap in search intent alignment.