I should mention that my suitcase was constructed using a heavier fabric-like material so I was not at all worried about the decoupage medium and material adhering to it. While I am confident that you could get similar results decoupaging a suitcase that is made of a less porous material, like plastic, the finished product might not be as durable as mine.
I dug through my fabric bins and found a collection of fat quarters I have had for years. I thought these fabrics had a bit of a vintage look and would go well with the brown handle and trim.
If you want to learn how to decoupage your own suitcase, begin by gathering your supplies...