Lay out your t-shirt on a flat surface. Using a marking tool like chalk or a marker, Trace out a V shape from the front collar of the shirt to the bottom (see photo)
Cut along your marking, making sure to only cut the front of the shirt. Clean up any choppy lines.
Your shirt is now ready to wear! Put the shirt on and use each newly cut side to tie together in a knot. P.S. make sure to wash off any left over chalk markings before you wear the shirt out :)