Feature Engineering Cheat Sheet

Feature engineering is the process of transforming raw data into meaningful features that improve machine learning model performance. It sits at the intersection of domain knowledge and data science, converting observations into numeric representations that algorithms can interpret. While automated approaches exist, manual feature engineering remains critical—selecting the right transformations, encoding strategies, and scaling methods often determines whether a model achieves mediocre or exceptional results. A key principle is always fitting transformations on training data only, then applying them to test data to prevent data leakage. Understanding these techniques empowers you to extract maximum signal from your data.