[header] How to shrink a cotton t shirt [title] Prepare a large, boiling pot of water. [step] Clothing companies often stretch out their fabric so that less cloth is needed to manufacture a shirt. Washing the cotton shirt, or submerging it, in warm water will help the cloth in the shirt shrink back to its natural state. 
[substeps] If you want to avoid the hassle of buying a shirt that's too big and shrinking it yourself, look for pre-shrunk garments when you shop. Pre-shrunk shirts are increasingly common.