Create custom error pages for a better user experience:
For IIS/.NET (web.config):
```xml
```
For Apache (.htaccess):
```
ErrorDocument 404 /errors/404.html
ErrorDocument 500 /errors/500.html
```
Best Practices:
- Include navigation to help users find content
- Add search functionality
- Include contact information
- Keep the design consistent with your site
- Log errors for troubleshooting