A useful starting point
Keep the declaration requirements nearby. Check each group independently and then review the whole hand. Confirm that every card has been considered once.
Try it in practice
If you are using an app, practise the declaration control in a tutorial. Learn how the app displays an invalid attempt before depending on memory during a timed session.
Take one idea forward
Choose one question to revisit next time. Use the current rules for your format and keep the session comfortable for everyone.