lace insert in top photo tutorial BASICALLY in a nutshell here…buy a tee…buy some lace…pin the lace to back of tee. Sew lace on the tee. Cut out fabric that is under the lace, but leave about and inch to sew back to the sides for stability.
Thinking about this for a workout shirt! DIY Project: No Sew Tank Top from an Old T-Shirt - I already did this and it took less than 15 minutes. Used one of my husband's old t-shirts. Wearing it now and it's super comfy.