For framing our embroidery, we are going to use white (or some light color) felt fabric, we need one A4 sheet.
Separate the hoop you are using. Place the inside ring on a piece of felt and use your disappearing ink marker to trace around the inside of the ring. Cut out the circle of felt and set it aside.
Place your finished embroidery in the hoop, taking care to align the design with the screw at the top so that it looks perfectly centered.
Pull the fabric as taut as possible, but not so taut as to distort the image. Tighten the screw as much as you can; using your fingers first, and a screwdriver second if needed.
Trim the excess fabric, leaving about 1" around to work with.
Start at the bottom and take large running stitches all around the outside edge of the fabric. Be sure to use a long enough piece of thread that you can go all around the outside of the hoop. When you reach the beginning of the stitches, gently pull the ends of the thread to gather the edges in toward the center.
Keep pulling slowly and gently, adjusting the folds toward the center until the fabric lies flat.
Tie the ends of the thread in a large knot close to the fabric, then you can take a Backstitch or two to secure the gathering.
Place the felt circle on the back of your hoop and pin with a few needles to keep it in place while sewing.
Use thread that is the same color as the felt to make the stitches disappear, I like to use regular sewing thread-doubled (you can use embroidery floss as well, but it will be more visible).
Blanket stitch around the entire perimeter of the circle.
If you were drawing the pattern with heat sensitive pen, use your hairdryer to remove the traces of ink and you are finished!!!
Video tutorial: How to back an embroidery hoop