Use the hands on approach if you study the 2d and 3d shapes. This creative way makes you better understand the relations between the 2d and 3d shapes and it helps you to develop the visual sense.
Develop projects that challenge you to create 3d shapes putting together three or more 2d shapes.
For instance, if you want to craft a cube, use several tools such as 1 piece of cardstock, 1 scissors, 1 ruler, glue or adhesive tape, pencils.
Start the crafting project by drawing 6 equal squares on the cardstock. The ruler and the pencil will help you to draw the equal squares. Then, cut up all 6 squares.
The last step is to assemble the 6 squares such as to create the cube.