To make the easier cards more difficult and to help her learn how shapes combine to make other shapes I do one half of the design with large shapes and then lay out smaller shapes for her to use to finish the other half of the design. You can also talk about mirror images and symmetry while doing these type of designs.
I used this card to teach her how two shapes together create a new one. To make this harder do not use the card so your child can not see the outline of the shape they need (put out a number of shapes so that they have to pick out the correct one). Another fun activity is to cover up one of the images in the row- for example cover up the semi-circle in the first row, one of the semi-circles in the second row, a square in the third row and the square in the last row.