World Duty Free is a company that sells items in airports. They sell mainly alcohol, cosmetics, perfume, souvenirs, fashion accessories, foods and tobacco products. It is wise to know a bit more about the range of items that they sell, although there are 17,000 of them, so you will not be expected to know all of them.
As the stores are located in airports, it is unlikely that you will get the opportunity to look around one before your interview. Therefore it is wise to have a good look at their website and find out more about them that way. The website has details about the specific products that they sell and so you will be able to find out more that way.
It is very likely that you will be asked why you want to work for the company. Having an answer to this question can be difficult. You may have good reason to want to work for them, perhaps always wanting to do so or enjoying the retail travel experience. However, if you have not always had an ambition to work for them, then you need to come up with something. Perhaps you have heard good things about the company that you can report back or it is just the type of environment that you really like working in.
It is likely that you will be serving international customers and so you will need to show in your interview that this is something that you are capable of. You may have a basic understanding of more than one language which could be worth a mention. If you are well travelled or used to dealing with people from different countries, then this could also help you.
Obviously retail experience will be important as well, so make sure that you can show that you have plenty of this or at least are used to working with other people. You need to show that you have good customer relations skills. If you are applying for a particular department, such as beauty, then it is good to mention experience that you have of working in that area in the past.