Step 2: Prep
If your shirt is new, wash and dry it.
Cut your wide making tape into 50 relatively equal lengths. I did this by laying the tape in strips onto a cutting mat and then using a paper cutting wheel and acrylic grid ruler. For a large man's shirt, I cut 2" wide tape into 3" strips. It really filled the front of the shirt well. For smaller shirts, us narrower tape and cut into smaller lengths.
Lay the shirt, front side up, on a flat surface. Slide a piece of flat cardboard, plastic, or other material into the shirt to prevent bleeding paint from transferring to the back of the shirt.
Lay your pieces of tape out in whatever pattern you'd like, with the edges of the pieces just touching their neighbors (no gaps). For this large man's shirt, 5 columns of 10 was ideal.
Finally, apply a tape border around the entire grid of tape.