Low r2 for machine learning regression models. how to solve

To solve the low R2 of the machine learning regression model, you can try the following methods: 1. Increase the quantity and quality of training data; 2. Change the structure of the model to increase the complexity of the model; 3. Change the training method and use more advanced Algorithm; 4. Adjust regularization parameters to prevent model overfitting; 5. Feature engineering to mine more effective features.