To fully understand a genre of art, the best approach would be:
Research its history, development, and characteristic style.
Understanding the historical context, key movements, influences, and stylistic elements that define the genre provides a solid foundation for appreciating its significance and evolution. This comprehensive knowledge will also enhance your ability to critique specific works within that genre effectively.
While critiquing examples of art and studying works from the same time period can be valuable components of your overall understanding, grounding your study in the genre's history and characteristics allows for a deeper insight into both individual pieces and the genre as a whole.