You can use many different types of paint, but they are suitable for fabric. One way to make a shirt with custom design is a template that you like and some paint.
If you can not find a template you like, you can do yourself, dibujnado on cardboard and cutting. Another way to paint your own t-shirt is done with a special pen for fabrics, so you can write the words that you like.
Very original, is sewing on a shirt different basic sewing tools. Choose an area of the shirt sewn over the area, safety pins, original pins, brooches, buttons and even mézclalñe a piece of tape, before giving way you like.
In this way you get a very original shirt, fashionable, and by you.
Another way to customize your shirt, is to choose several pieces of fabric that you like and combine them with the color of the shirt you want to customize, colors and prints that combine well to each other.
Sew the fabric pieces, place them on each other, sew some topped, others not finished, others frayed, vente sewing the pieces as you like.