Whenever the soil is dry, its often good to let the soil completely dry out before watering again, this increases root growth as they are going to search for water, and also help to keep fungus and any other nasty growing things in the soil from growing when its kept to damp. Other then that nobody on here can tell YOU how often to water your plants, your soil, size and type of pot you are useing, strain, heat in the room, and 20 other factors are included in this equasion. Water your plants when they need it.
It should be moist, and if you can get a clear top, mist it, and set it over the seedling to make a greenhouse, it helps the seedling grow, but once you water it wait a day or 2 and check the moisture, i usually stick my pinky in the soil about an inch or 2 to feel for moisture, but when it gets older you should get a meter for everything