I find charisma to be easy, except for the jokes part. My sim has 102 aquaintnaces and 92 friends. She's maxed everything, but the jokes part, because she's too busy to joke around (lol).
If your sim is good at guitar, or singing, they get the first part of charisma easily. Then they throw a party and their aquaintances become friends. Then they throw more parties and the friends become best friends. Simple!