Design feature flags to minimize dependency bloat while maximizing flexibility for users. Each optional dependency should be tied to a specific feature flag, allowing users to enable only the functionality they need. Key practices: 1. Express dependencies between features explicitly in Cargo.toml 2. Create granular feature flags for optional dependencies 3. Use conditional compilation for platform or feature-specific code 4. Consider feature organization when adding new functionality For example, instead of requiring a dependency for all users: ```toml # Avoid this approach - forces dependency on all users rt = ["tokio/rt", "tokio/sync", "futures-util", "hashbrown"] ``` Use a more targeted approach: ```toml # Better approach - separate optional functionality rt = ["tokio/rt", "tokio/sync", "futures-util"] join-map = ["rt", "hashbrown"] ``` For platform-specific features, use appropriate conditional compilation: ```toml # For platform-specific features [target.'cfg(all(target_os = "linux", feature = "rt"))'.dependencies] # Linux-specific dependencies here ``` When organizing features, aim for a balance between granularity and usability, with a "full" feature that enables everything for convenience.