Model training and optimization is the process of systematically improving neural network performance through algorithmic techniques that adjust weights, manage learning dynamics, and prevent overfitting. This encompasses gradient descent methods, learning rate strategies, regularization, and various training tactics that determine how effectively models learn from data. Understanding these mechanisms is essential because even the best architecture will fail without proper optimization—choosing the right optimizer, learning rate schedule, and regularization approach often makes the difference between a model that converges to high accuracy and one that struggles or overfits. A key mental model: optimization is fundamentally about navigating a high-dimensional loss landscape to find parameter values that generalize well, not just minimize training error.