Some resources:
- Accessibility Insights for Web -> https://accessibilityinsights.io/docs/en/web/overview/
- GDS Styles -> https://design-system.service.gov.uk/styles/
Example 1, default focus indicator is a slight change of font colour (placed here on Reports) but you may need to look closely.
Example 2, with focus indicator as a yellow highlight.
Example 3, introducing a context sensitive 'skip' shortcut to the New Ticket button. Pops into view if user begins using for keyboard only navigation and want to skip straight to the new ticket button.