When you are done with your cross stitch piece, you have to decide how to display it. One of the most common is in a hoop, either the one you stitched in or one purely for display. For this you will need your hoop, white felt, embroidery thread, and, optionally, some ribbon for a hanger.
The first step whenever you finish a cross stitch piece is to wash it using a mild laundry detergent. My favorite way is to use a no-rinse detergent like Soak or Eucalan and soak the whole piece in a bowl with the soap and water for around half an hour, and then let it air dry overnight. This will get rid of any water-eraseable markings along with most marks from your hands. You can also toss in a color catching sheet into the soaking water to help prevent color bleeding.
Once the piece is dry, flip it facedown and iron it on the rear at a medium setting, being sure not to linger too long in any one spot to prevent burning your fabric or threads. This will get out any wrinkles that may have shown up while it was drying.
Take the inside of your hoop and trace around it on a piece of felt. Cut this out and set it aside to cover the back of the hoop at the end.
Place your piece back into the hoop, making sure it is centered and that the screw is centered at the top, and trim excess fabric to around 1 or 2 inches outside the hoop. Thread 3 or 4 strands of thread into your needle and sew a running stitch all around the edge of the fabric, leaving tails at the beginning and end. Pull both tails to bring the excess fabric around the back of the hoop and tie the tails together to hold it in place.
Using a blanket stitch, sew the felt to the back of the fabric on the center of the hoop. Use more embroidery thread or some ribbon and create a hanger for your hoop, or lean it on a shelf.
Here’s a video showing the whole process: