Gather everything you need.

Lay the shirt out flat, making sure the seams are aligned and laying straight.

Sketch in the cutting lines with your chalk pencil, spacing them about 1.5cm apart. Places to put these lines include the sides of the shirt, the shoulders, the tops of the arms, and even as a detail on the front.

Start cutting! Carefully take your scissors to the garment, making sure to line up the front and back when cutting through both.

Stretch out the loops on the sides of the t-shirt, gently pulling until they’re thin strips.

Cut these loops in half using your scissors.

Match the ties from the front and back of the t-shirt together, then tie them in a double knot. Make sure this is tight enough to survive the washing machine, but not too tight! You can even do this step as you wear the shirt to get the best possible fit.

Stop here if you’re happy with the sizing or keep going to alter the sleeves.

Cut along the armpit seam, stopping about halfway. Cut through the loop you’ve made and tie it together under the armpit, thus tightening the sleeve.

Sketch more chalk lines on the underside of each sleeve, spacing them as you did for the other lines.

Cut the lines out and cut through the loops, then tie together. Make sure you’re checking how tight the sleeves get as you tie. After all, this shirt is meant to fit you and only you!

Voila! You have a completed shirt, tailored beautifully to fit your unique shape.