Children's shoes are becoming harder and harder to find in op shops (thrift shops). I think this is partly because so many contemporary children's shoes are so poorly-made. Even brand new ones only last three or four months before falling aprt. But there is one type of children's shoe that is still being manufactured to exacting standards and in quality materials - tap shoes! I found these tap shoes in an op shop and removed the taps (they're merely screwed in). Now my daughter wears them to school. More to read on my second-hand-shopping blog.
from Charlotte Russe, although I don't think it's available anymore
I choose not to cut out the fabric underneath the lace - I actually tried a version where I did but did not like the way that it looked on me (probably more suited to someone in their 20's)
I don't have step-by-step photos of this project because there is really only one step - cut your lace to the shape you would like, lay out on the back of your shirt, pin in place, and sew down - an easy little way to incorporate the lace trend into your wardrobe.