AnneLM's Profile

Light, light, and more light. There are very few herbs that do not need direct sunlight. Even if this is a south facing window, there may be trees or an overhang outside that cut down on the amount of light that is coming through the glass. The glass itself, especially UV glass, also cuts down on the amount of light the plants receive. I am able to grow rosemary inside over the winter in an unobstructed east facing window, but it really limps along until I can get it outside again. Artificial light helps if it is close enough to the leaves (just a few inches away.)
The soil should be loose and fast draining. Most herbs prefer to be on the dry side, so water infrequently, but when you water you need to be sure the water gets to the entire root system. So I disagree with the advice not to flood the plant. Take the pot to the sink and water it enough so water runs all the way out the bottom, and let it drain before putting it back on its saucer. Do not allow any water to sit in the saucer below the plant. Then let the soil dry out to an inch below the surface of the soil before watering again. This could be in a few days; it could be over a week. It depends on the temperature and humidity of the room, the type of soil, and the size of the pot in relation to the root ball.
If the window they are in is very cold and the soil is damp, they might rot, but on the other hand they should not be too close to a heat source.
I hope all this helps!