Obviously this depends on the time of year, the dryness of the soil, and so on. Ideally, the water level in the soil should be about 3 inches for your herbs to reach their full potential.
Most herbs like plenty of light so a sunny kitchen would be okay, but try to avoid dark places.
Absolutely! Outdoor pots are the best place to keep your herbs.
Most diseases are carried by water and using compost means you can keep any overhead watering to a minimum because it will naturally stay quite moist.
You should try to use fairly fertile soil. In fact, when it comes to herbs, compost very often produces the best results.
The majority of herbs are happiest when they are in the full sun.
The great thing about herbs is that you can plant them all year round.