Do you ever pack with the thought of your luggage being lost? If not, why not? Now is the time to start!
You can start by sorting out the things you are planning to take such as clothes, shoes and other personal items (such as deoderant etc) and divide them in half. Do this for every member that is travelling. Put one section in one bag and the other in another bag. This way, if one does happen to get lost, you will always have clothes for the immediate on hand.
Never put your daily medication in any bag. Always carry these with you in person!