Instructions
Do Your Research
Find out what 10-year-old girls like. If you have a daughter, you will most likely know what she enjoys; of course, you can simply ask any of them what they like.
Research the top trends for preteens in the current year. Use the Internet to your advantage, utilizing search engines like Google Trends (see the Resources section) to search for keywords such as "what do preteen girls like" and "children's toy trends" with the year in the search field. There are literally thousands of results out there that will help you determine what to make your computer game about.
Venture to department and toy stores and ask the sales associates what they think girls in that age group like, as they see children and their parents picking out toys all the time.
Create the Game
Download a game-creation engine (many are listed in the Resources section).
Learn how to use the program. Many of the programs today include help files that you can read to learn about how to make the game. You can also visit forums and websites made specifically for that engine and speak to real people about how to make your game.
Get the media. This includes graphics, music and sound that can be used in your game. You can find many free resources on the Web as well as in the Resources section below.
Create and test the game. Your first game may not be perfect, but the more you add to it and practice making games, the better at it you will become. You will be able to make a game for your 10-year-old daughter or your friend's daughter in a short amount of time.