If your luggage doesn’t surface when arriving at your final airport destination, go directly to the airline’s office to fill out a lost luggage form.  Make sure you obtain a phone number to call for follow up and a tracking number.  Having ID on your luggage is a bare minimum, but also some type of unique identifier such as a colored tag or strap will help find it more easily.  Be able to give a complete description of your bag and where they can deliver it when found. – better yet, have a photo on your phone!

Ask what compensation is available for replacing lost clothing and toiletries.  If your bag is never found (fortunately, a small percentage), make sure you keep receipts to submit for allowable reimbursements through your travel insurance or the airline carrier.  Your rights are described under this governmental website, Department of Transportation.