Open the graphic-design or paint software of your choice on your computer.
Create a new graphic image large enough to accommodate your dice template. Click "File" in the upper menu, then select "New" or "New Image" in most software menus. The software will prompt you to enter the dimensions of your file size in inches or pixels. Ensure that it is at least three times as tall and four times as wide as the width you'd like your dice to be.
Draw a perfect square shape using the shape-drawing tool of your software, if the software has it. Hold the shift key down as you drag the tool to get a perfectly symmetrical square. If your software does not have a shape-drawing tool, draw a line, then copy and paste it three times, positioning it into a perfect square shape. Merge the lines together so that the square is a single object, not four layers of lines.
Copy and paste the square five more times into the document.
Click and drag the squares around so that their sides are flush with each other in a cross formation, with three squares across and four squares down. This will ensure that, when printed, your dice template will form a cube.
Create smaller shapes to join to one of the cubes in the long row of squares, and both cubes on the short row. This step is optional, but the tabs will make it easier to glue or tape the dice together when you print it and cut it out.
Decorate the six sides of the dice as desired using your graphic software.
Save the dice template to your hard drive.