I got the original shirt from a thrift store, and the lace from JoAnn's!
Step 1: I found this shirt on AliExpress (a big contributor to fast fashion) as my inspiration.
Step 2: Try the shirt on and measure how much you want to crop it. For me, I wanted to make the edge raw, so I didn't add a hem
Step 3: Mark on the shirt where you want the lace to be, and cut out the triangle at the top of the shirt.
Step 4: Buy lace from a local craft store and measure how much you need from the top of your breast, to the bottom of the other
Step 5: Pin the lace and sew along the long sides of the lace, and you are all done!