Lay the T-shirt flat on a table
Cut off both sleeves along the armhole seams
Cut the neckline lower if you want a deeper singlet shape
Trim the sides inward if you want a more fitted look
Cut the bottom hem straight or slightly curved
Try it on and adjust any uneven edges
Fold the raw edges inward and sew them if you want a finished look
Leave the edges raw if you want a quick no-sew singlet
Wash the singlet after cutting to soften the edges