I would also shrink the strips before sewing them on.

You can just soak them in the sink, or a kettle, or a bowl in hot water - take them out and let them dry on a towel or a drying rack.

came out great. just iron before you gift them. let her worry about the wrinkles. I do mine like that for all occasions

I would iron the towels before I sewed fabric strips on and would also wash the fabric before putting it on.

When I have fat quarters or small pieces of fabric that need to be washed especially red I put them in a lingerie bag. I have three sizes: largish, medium and 3 individual small ones. I then put them in the regular wash with the appropriate colors. Then iron and put away or use. Unlike some I like to iron. It is meditative especially listening to a good book on CD or my phone.

I would wash the towels and strips so they both shrink. Press the towel and strips and use some starch on the strips to help turn the raw edges. Also because of shrinkage I'd cut the strips a little bigger in width and length before washing to insure they will fit on the towel the way you want them.

Made lots of these for gifts. https://sew4home.com/projects/kitche...der-tea-towels
This is a great sit. Check out the pear towels also.