Cotton is a durable, soft fibre, and most clothes today are made of it. Unfortunately, it does have one serious fault: It tends to shrink when washed and dried. Contraction is in the nature of the cotton fibres, and there isn't much you can do to stop them from shrinking after a wash. However, there are a few steps that can moderate the shrinkage.
Hand-wash your clothes. This isn't really an option for most busy people, but the first step in fighting shrinkage is hand washing. If you have an item that you know is prone to dramatic shrinkage (more than 10 per cent), treat it as a special case and hand wash it.
Wash in cold water. Whether it be in a machine or by hand, always wash cotton in cold water. It is easier both on the shrinkage and the cloth overall.
Give your clothes a stretch when the come out of the wash. This will counter any shrinkage while the clothes are still pliable.
Line dry your clothing. The heat and rapid drying of an electric or gas clothes drier might be convenient, but it also shrinks clothing as quickly as it dries them out.
To avoid shrinking issues altogether, try to buy preshrunk clothes, or clothes that are not 100 per cent cotton.