Identifying common mistakes made by beginner mappers and knowing ow to fix them is important to improve the quality of the map. If you spot something which needs fixing, send a friendly message on the users' changeset on what was wrong and how it could be fixed. You can use this guide as a reference.
| Issue | Whats wrong | How to fix it | Tips |
|---|---|---|---|
| Overlapping ways |  A linear way goes over itself or another way with the exact same tags (note the arrows on the selected way) |
Delete the overlapping way, make sure there are no gaps or missing pieces left behind. | You can use the JOSM validator to detect these issues |