hey man
you will have the best healthy plant if you let her dry out between waterings. Just wait till the cup feels real light and the top looks real dry. Then when you water it drench it completely and then wait for it to dry again, and on and on. Obviously, you do not want to wait till it actually wilts, but like right before it does. Watering it just a little bit every day or every other day or similar, is the quickest surest way to kill a small seedling.