DIY / Drawing on tshirt

It is difficult to find a special tshirt for my son.

Tshirts selling in department stores are so common.

Thus, I try to make one for my son.

I cut a star shape hole first.

Then I use the rubber on the pencil as stamp, to stamp different color in the hole.

After finishing, I remove the paper and finish the remaining part of the tshirt.

As this is the first time I use the color for tshirt, I am not sure if the color will come out after wash.

I wash it once in water.

That is great! The color does not come out.

But the black color is not good enough. I use tiny drawing brush to outline the stars, but the lines' edges are not tidy.

Maybe next time, I have to buy some marker to draw lines.

Have you every draw tshirt by yourself? Can you give me some opinion on how to draw better?