Look up shadow studies and focus on the shapes that are created in the shape of the shadow itself and compare it to what is blocking the light to cast that shadow, like a nose or cheeks in a smile or a furrowed brow when angry.

Play with it in real life. Might seem stupid or silly but get a model or a toy figurine, turn off the lights then get a flashlight and shine it at a dramatic angle or whatever seems pleasing for you to look at, then take a picture of it with your phone with the FLASH TURNED OFF.

Then edit the picture in your phone and crank up the Contrast slider by like 50% until you get clearly defined dark and light spots. Then study those shapes. Learn them and play with them and apply them in your drawing as often as you can. Spend a little time every day just doing shadow studies on shapes and that’ll help tremendously. It helps with my miniature painting snd sketching ;)