Choose your personalities to fit the role you want your Sim to play. Neat Sims make very good stay-home cleaners. Outgoing and Nice helps a Sim looking to make family friends. Playful makes the wonderful interaction "Entertain" available more readily. An Active Sim is suited to be on-the-go and doesn't get uncomfortable easily.
For more Tips & Tricks for playing The Sims, including Time Management, building Skills, and getting more money, click here.