Air Circulation
In between Rinse and Drain cycles your sprouts do their growing. During that time it is essential that they can breathe. The best sprouting devices help them breathe, but you need to pay some attention too. There isn't much to it - sprouts can grow just about anywhere - as long as they can breathe, but don't have so much air movement that they dry out between Rinses.
We set our Sprouters on our kitchen counter. We don't mind the diffuse sunlight or the 150 watts of incandescent light. Light just does not matter much. A plant can only perform photosynthesis when it has leaves. Until then light has little if any effect, and they need to breathe - so don't hide your sprouts!