The first step was to die cut the window in the card blank and the overlay to insure that they matched in size and location. To do this it helps to do the die cutting from the back and actually draw in some reference lines.
The second step was to create the insert. I did this by making a smaller card in a complimentary color which will serve as both the window opening background and the text insert. For the window opening I created a design using rub-on green flourishes from Heidi Grace/Fiskars and some 3D glittered flowers and a rub-on text from K & Company/E. K. Success. It is critical that the design is visible when the card is closed but yet adds interest when opened.
The final card is (I think) beautiful and goes to show that windows can come in all shapes and sizes.