There are many different elements that can be used in effective learning games, but some of the most common are:

1. Positive reinforcement – Giving players rewards for completing tasks or learning new information can help them stick with the game, and help them learn the material in a more effective manner.
2. Interactivity – Keeping players involved in the game by requiring them to make choices or take action in order to progress can help them learn more effectively.
3. A variety of tasks – Providing players with a variety of tasks to complete can keep them engaged and ensure that they are learning different aspects of the material.
4. A challenging but achievable goal – Creating a goal that is challenging but achievable can help players feel successful and motivated, and can help them learn more effectively.
5. Flexible gameplay – Making the gameplay mode and tasks available to players in a variety of ways can make the game more adaptive to the individual player, and can help them learn more effectively.