Water lightly only after the soil gets dry every 1-2 Weeks, depending on conditions. Never overwater! The key is to watch your terrarium closely until you understand its drying pattern. Too much watering can be worse for the plants than too little.
Place in a bright area indoors, some direct sunlight is fine.
When the plants get as big as you want, pinch off the newest growth to encourage bushier growth.
Water at the base of the plants and not the leaves because they can rot easily.