1) Jeans or t-shirts. I prefer cotton t-shirts.
2) Textile paint and acrylic for achieving varieties of colors. I just bought myself 5 textile colors namely: RED, BLUE, YELLOW, WHITE, BLACK; and a set of acrylic just for mixing to achieve more colors. Bear in mind that you should know how to mix paint and colors, just about the basics of color mixing. You can always use the trial and error method for color mixing until you achieve the desired shade or consult this website
for more information.
3) Paint brush of various sizes (000, then 00, 0, 1, 2, and up) which will vary according to the measurement of your design.
4) Mixing plate, containers, for mixing the paint.
5) Any measurement tool: T-square, Ruler, Tape Measure.
6) Pencil or tailors chalk for drawing the outline.
7) Any hard material that would fit inside the jeans and shirt like chopping board or thin drawing wood board.
8) Design pattern.
9) Freehand drawing skill.