Practice.
Practice-practice-practice.
When I was a kid and had to do household chores, I absolutely hated to fold laundry. She-who-must-be-obeyed decreed that t-shirts had to be folded into thirds lengthwise, then the long strip of folded shirt had to be folded yet again into thirds to create the neat, square package to fit in the drawer.
My beginning efforts resulted mainly in lumps.
Early ironing lessons for kids back in those days meant handkerchiefs and pillowcases. She-who-must-be-obeyed decreed pillowcases had to be folded in a fashion similar to t-shirts. Early efforts at ironing pillowcases also resulted in lumps, but they were nice, smooth lumps!
Now that I’m an old lady, I can fold t-shirts blindfolded. It just takes practice!
~VOW