Buy a Sharpie Rub-a-Dub Laundry Marker. This fine point permanent marker is available for under $2 at most retailers. You can find it fabric and craft stores, like Jo-Ann, or your local office supply store, like Staples and Office Depot. It is also available on Amazon.com and on the Sharpie.com Web site. The Rub-a-Dub Laundry marker is only available in black, but it allows you to easily write on clothing without fear that it will fade away. This marker is nontoxic and it will stay permanent through multiple washings and even dry cleaning.
Lay your piece of clothing against a flat surface. This makes it easier for you to write without any mistakes.
Think carefully about the location on the piece of clothing that you want to write on. Sharpies are permanent markers, so you do not want to make an error that you will regret later on.
Remove the cap from the Sharpie Rub-a-Dub Laundry Marker. Carefully write what you want on the piece of clothing.