The SpatioTemporal Asset Catalog (STAC) specification is a common language for describing geospatial information that is flexible enough to extend across domains and use cases. In this talk, we walk through best practices for building STAC catalogs and using STAC extensions, using real world examples. These best practices are informed by documentation, conversations with STAC contributors, and discussions within the wider community. We survey the ecosystem of open-source STAC software, which includes libraries and tools written in Python, Node.js, and more. We show examples of reading, modifying, and writing STAC catalogs with a selection of software, including PySTAC and stactools, and we show which metadata to include in your STAC objects to ensure interoperability with powerful tools like xarray and pandas. Whether you are new to the STAC ecosystem or an experienced contributor, this talk will provide you with the context and tools you need to build your best STAC!