The Guidelines:

• Guideline 1: Appreciate the significance of the object.
• Guideline 2: See objects as bundles of services, not bundles of data.
• Guideline 3: Design Service-Oriented Objects that use their state to decide how to behave.
• Guideline 4: Use Messengers to transmit information.
• Guideline 5: Use Flyweights as pluggable nuggets of behavior.
• Guideline 6: Use Immutables to represent values of abstract data types.
• Guideline 7: Don't send your objects out naked.