The Creativity Skill can be developed on the activity table as a child sim and easel as an adult. Increasing this skill will unlock new Activity Table Drawings, Dollhouse Interactions, and Socials!
Mental Skill is built on the science table and chessboard. Increasing this skill will unlock new Science Table Potions, Computer Interactions, and Socials!
Social Skill can be developed on the dollhouse and stuffed animal. Increasing this skill will unlock Sim.tv on the Computer, Doll Interactions, and Socials!