Watering herbs is quite simple. They mostly prefer dry soil in between watering. Although some herbs tend to need a bit more water than others. Climate conditions have a large impact on an herbs need for water; for example if your herbs are outside in hot temperatures they will tend to need more water. Sun exposure is also a big factor in the watering process, most herbs need full sun which will also cause the soil to dry quicker, hence the need for more water. Proper drainage is also important for growing healthy plants, so if you have a pot with holes in the bottom you should keep them unplugged, especially if outdoors, if an herb garden is indoors, either unplug and use a drainage dish underneath your pot, or if you chose to leave the plug in, then it is very important to water even less! If you over water herbs the roots could rot.
Rosemary likes dry soil, so let soil dry in between each water, every other day is usually ok. Rosemary also does not need full sun, it can take partial, meaning 2-3 hours per day is ok.
Young Basil plants need to be watered daily, but again not over watered due to possible root rot. Basil also needs full sun, no less than 5 hours per day.
Thyme needs full sunlight as well, minimum 5 hours daily, but dryer soil, every other day, letting soil dry in between watering. Thyme is very susceptible to root rot if over watered.
Lavender plants and Oregano like similar growing conditions.