If you can't get the whole costume accurately, you might wonder which ones are the most important. Well, the answer actually depends on the Katara cosplay you are doing. Generally, you need to stick with wearing the necklace, hair loopies, and the blue top for the classic Katara outfit. The combination of all these items is definitely going to help your cosplay be more recognizable. You can go away with not wearing the fingerless gloves or the boots but never with the three features mentioned above.