Self-tuning is a process where a computer can adjust itself to work better. It's like a person working on something and the more they do it, the better they get. When a computer uses self-tuning, it's constantly analyzing its own performance and changing the settings that it uses to get the best possible results. For example, if a computer was learning to play a game, it could adjust the difficulty level of the game based on how good it was doing. That way, it would get better and better at playing the game.