How to increase a Sim's charisma:
- Have the Sim use interactions with other Sims from the special Charisma interactions section. Using these will improve the charisma skill.
- Read skill books.
- Practice speech at any mirror. Depending on your Sim's traits, the speech might be about world peace, world domination, etc.
- Take a class(?)
Charisma Abilities
As Charisma increases, your Sim gains access to various abilities. These abilities are in the form of social interactions.
- Level 1
- Friendly Greet
- Charming Introduction
- Level 2
- Amusing Greet
- Level 3
- Interesting Greet
- Get to Know
- Level 4
- Flirty Greet
- Level 5
- Affectionate Greet
- Smooth Recovery
- Level 6
- Funny Greet
- Level 7
- Impressive Greet
- Level 8
- Hilarious Greet
- Level 9
- Loving Greet
- Level 10
- Irresistible Greet
A couple of the above interactions are particularly notable: Get to Know and Smooth Recovery.
To use Smooth Recovery, your Sim needs to do something awkward in an interaction with another Sim. This could include flirting with someone who is just not that into you, talking about a subject that the other Sim hates (for example, talking about computers to a technophobe), or just being insulting or rude (using a rude greeting or mean interaction). If this causes the other Sim to have a negative reaction with two minus signs, the Smooth Recovery option might become available in the Friendly Interactions list.
The Get to Know interaction gives your Sim a better chance of learning the other Sim's traits. This is very helpful if you want to get complete the Personable challenge.
Charisma Requirements
Unlike most other skills, charisma has some requirements for getting to the higher levels: namely, making lots of friends. A Sim must meet the relationship and friend requirements to get to higher levels of Charisma. These requirements increase as the Charisma level goes up.