When planting in a pot, make the soil at the center of the pot lower than the soil at the sides of the pot (a nice dip in the soil).  When the plant is watered, water will flow to the center and soak into the soil.  If the soil is higher in the center, the water will flow to the sides of the soil and down between the soil and pot, leaving through the drainage holes without being absorbed by the soil.  If water isn’t absorbed into the soil, the plant will not be able to draw nutrients and water.