To prevent injury and optimise performance, it is important to wear a pair of specific badminton shoes. Playing badminton involves a great deal of twisting and turning, often at high speed, and can be fairly vigorous on your knee and ankle joints. To reduce the risk of injury, it is important to wear a pair of shoes with very good grip, cushioning and also support for your ankles. It is also important that you find a pair which are comfortable!
It is also worth taking steps to increase the lifespan of your badminton shoes. Once the cushioning is lost from the shoe, its protection and effectiveness is lessened, and thus injuries are more likely. Firstly, try and only wear your them for playing badminton or other indoor activities - don't go jogging in them! This will help them keep grip, and stop you slipping around the court. It is also worth replacing your in-soles if you feel the cushioning effect start to weaken!
The most important thing regarding badminton clothing is comfort. Generally speaking there are no strict rules about what you can or cannot wear, but you are more likely to play well when wearing something comfortable and not overly restrictive. The majority of players will tend to wear a polo shirt or t-shirt and a pair of shorts or skirt. It is a bad idea to wear jeans or other restrictive trousers to play in!