You should water a little bit, then wait to see if you have runoff water from the holes, if not water more until you get runoff water. Once you have water you need to leave the plant alone for 2 to 4 days, depending on the plant... Check the soil by pressing it gently, be careful not to break any roots, if the soil is humid wait until it's more dry, this will help the roots to develop, trying to reach the moist everywhere in the pot.

If you water too much the roots of the plant will suffocated and the plant will "drop"... You can see that happen if you underwater too.

Hope this help you out figure out when to water !