Succulents do not like to be over watered, in fact the prefer more of a dry soil. Let the soil dry out completely before watering.
Succulent terrariums prefer a small amount of water every couple of weeks.
Give a small to medium size terrarium approximately 1-2 tablespoons of water per succulent
Only use bottled, distilled or rainwater. If using tap water, it needs to be left out for a minimum of 24hrs to allow chlorine to evaporate.
Succulents prefer bright but indirect light. The best position would be in a bright room near a window.
EXTRA CARE TIPS
Succulents require fast draining soil. You can buy course succulent potting mix from a nursery or a garden centre.