How can I resolve 'dependency not found' build errors?

When encountering a 'dependency not found' error, first verify that the dependency is correctly declared in your project's build configuration file (e.g., `pom.xml` for Maven, `build.gradle` for Gradle, `package.json` for npm/yarn). Ensure that the dependency is available in the configured repositories (like Maven Central, npm registry). You might need to add the correct repository URL or update the dependency's coordinates (group ID, artifact ID, version).