Let your plants give you the feedback. If they're young they can't hold much water in their tissues, so check them every day and if they show any wilt (when soil's dry) then it's time to water, GENTLY. I prefer to keep them in a tray and put water in the tray and let the water be soaked up by the soil. I have no perlite or vermiculate mixed into my starter soil, so it retains moisture a lot better.
Also, upper left, GrowFAQ, you've got some reading to do.