Ornamental ginger likes high humidity, a lot of filtered, bright sun, and a pot with good drainage. Also, you want to keep the soil moist but not soggy—a soggy soil will cause yellowing of the leaves. My suggestion is to let the soil dry out about 1-2 inches down in between waterings if it's a smaller pot, and 2-3 inches down if it's a pot 8 inches or more in diameter.