Things You'll Need
Instructions
First, you want to design the layout of your game board. You can get blank game board templates or create your own. You can use a computer drawing program to design one and print it out. If your are artistically gifted you can draw it free hand if you want.
You want to transfer your design to the poster board. I would suggest tracing the outline of the design and drawing it onto the poster board with a pencil. If you make a mistake it is much easier to erase it in pencil than it is with pen or marker. However you can print out the design off the computer cut it out and paste it onto the game board.
I would suggest decorating your board game on the poster board at this point. You can use markers, colored pencils, construction paper, stencils, and graphics printed off computer. Cut out and paste construction paper, stenciled shapes and graphics to the poster board if you choose to decorate it that way. Have fun and be artistic.
Your game board does need a strong backing. I would suggest using foam board. Take a strong bonding glue such as craft glue or rubber cement and spread the glue around the edges of the foam board. Lay your poster board design on top and press firmly. Let it dry for about a day. After it is done drying you can play your game!