Tried and True

There's no need to forgo your fabric and acrylic paints! Instead, it's a matter of painting smart. When using one of these traditional paints, use a textile medium mix-in to adhere the acrylic to the cotton fibers, like Nat at NatSprat did. Also, once the paint dries, be sure to follow up with the instructions on the paint bottle to make the most of your design's vibrancy.

Unconventional May Be the Way to Go

Instead of resorting to acrylic and fabric paints, break out something a little more unconventional. For instance, chalkboard paint holds strong and lasts through washes, according to the Crafting Chicks. Also, Tee Juice sets permanently with the heat of an iron as demonstrated by Melanie Royals for Paint + Pattern. Something you wouldn't think of using in the first place may just be the trick to a permanent DIY design.

If You Like It, Then You Should Have Put a Stamp on It

Okay, so you don't have to use stamps solely, but trying different ways of "stamping" a painted design onto the tee helps the design to last longer. Doilies, stencils (Ed Roth's are great), stamps. There are so many possibilities. A DIY stamp like this one from paunnet presses the paint firmly onto the T-shirt. Or, by ironing down a freezer paper stencil, you can paint a solid design onto any shirt with a template that stays in place, as Samantha did on The Compound Eye of a Dragonfly. If you think it, you could probably use it to paint your tee.