Instructions
Determine goals. Every successful game, from Simon Says to Monopoly, has clearly defined objectives. Simon Says requires players to wait for Simon's permission before completing a task; Monopoly requires players to buy property. Your game should have objectives that are appropriate for the age group you are targeting.
Write rules. Most games require strict rules to ensure players all have the same obstacles and advantages throughout the game. Decide on the rules that apply to your game and write them down. The rules shouldn't be too complex or too simple.
Create game pieces or equipment. If you've designed a board game, make a template of your board and cut out your pieces. If you've made another type of game, buy or create the equipment (such as hoops or buckets) you will need to play the game successfully.
Conduct a trial run. Gather enough people--preferably in the age group your game targets--and play the game a few times. Follow the rules you've created to ensure they are reasonable for the game and the ages involved. Make note of anything that works well or that doesn't work. Make any necessary changes to your game and repeat the trial run until the game goes as you envisioned.