To design your own maze, either use an online maze generator or draw it by hand using one of various methods. MazeGenerator.net and PuzzleMaker.DiscoveryEducation.com both provide maze generators that make multiple types of mazes, including square, circle and cutout.
To use MazeGenerator.net, select the style you would like, such as orthogonal for square or rectangular mazes and theta for circular mazes. Pick the number of cells and entry location to define the maze design. Use the advance settings for extra control. Advanced option E controls the length of the maze solution with higher numbers making for shorter solutions compared to the size of the maze. Advanced option R controls the length and prevalence of dead ends.
To use the maze generator on PuzzleMaker.DiscoveryEducation.com, type in a title, select a shape for your maze, define the maze's size, and pick the number of pixels for control over resolution. Picking a higher pixel number creates a sharper image for printing.
One method to create a maze by hand uses a simple grid. Using a ruler and pencil, draw a large square or rectangle to the size of the maze, and add internal lines at every quarter inch to create the grid. Select start and end points, and mark out a snaking path, box by box, between the two points. Fill the rest of the maze with dead-end paths, draw over the final pencil lines with pen, and erase the remaining pencil lines.