With the right sides together, line up and pin the long edges of your top and back layers to each other.
Sew down both pinned sides with a 1.5cm seam allowance. Turn right sides out and set aside.
To create the frills, begin by taking your long pieces and folding them in half lengthwise, right sides facing inward. Pin in place at the short ends.
Sew down each short edge.
Iron flat your placemat base, making sure it's right side out. Do the same for your 2 long rectangles, remembering you want them right sides out.
Now to make the frills, change your sewing machine stitch length to between 3-4.
Taking your frill pieces, sew all the way along the cut edge with a 1cm seam allowance. DO NOT backstitch at the beginning and end. Stitch another straight line the same way with a 1.5cm seam allowance. Remember to leave long tails for your thread.Repeat this step for both pieces. Now to gather. Taking the 2 top threads in your right hand, holding the fabric in your left, gently pull away. Turn around and gather from the other side as well. Repeat this step for both pieces until they are gathered to the length of 34cm long. With your placemat base turned inside out, pin your gathered frill in between the top and back fabrics so raw edges are aligned.
Make sure your stitch length is back to a smaller setting Sew along the pinned edge.
Turn right-side out and iron flat if needed. Top stitch 1cm away from the seam you just sewed.
Turn inside out and repeat step 11, except leave a small opening about 2 Inchs long.
Sew the pinned edge, remembering to leave the opening.
Using the opening, turn your placemat back to right side out.
Carefully fold and pin the opening seam shut, then top stitch the side shut, again 1cm away from the seam.
Do one last iron if necessary, and you're done!