Learned that lesson the hard way too, killed my first ficus in about two weeks because I kept "checking" the soil and watering it every time it looked slightly dry on top. The trick nobody tells you is that the top inch of soil can be bone dry while the bottom of the pot is still soaked, so stick your finger down a couple inches or just lift the pot and feel how heavy it is. Only water when it feels light and the soil down deep is dry, then soak it until water runs out the bottom and don't touch it again until it dries out. Also make sure the pot has actual drainage holes and dump the saucer after, because sitting in standing water is what really finishes them off. Ficus roots need air, so wet feet for more than a few days and they start rotting from the bottom up. It's way easier to bring one back from being too dry than too wet, so when you're unsure, wait.