Luggage

What do I have to do? First of all be very careful about what I pack for a trip. No extras, none! This is the second trip in a row that my suitcase has not arrived. Can you believe it? The first trip was to Paris, Texas and thank goodness, we had planned to stay one night in Dallas before going on to Paris. The luggage arrived the next morning and we were just about to head out of the airport after checking when my husband received a call on his cell phone saying that the luggage had arrived and been located. We did not trust the airline and had gone to check about the luggage. This time it was just my suitcase that did not arrive in Toronto.
Now, please explain why when we checked in all the suitcases at once that one does not arrive in Toronto with the rest. The other time, the airline switched planes and all small luggage did not arrive.
I will be a happy person when my luggage arrives.