Hi! Since you asked for help, I'm here to teach you some new tricks.
1. Give different textures. Using curved lines isn't the only way to draw hair. Experiment a bit.
2. Volume. Hair doesn't always just sit on top of someone's head- usually hair is above the hair a little bit because it has volume.
3. Give out-of-the-box hairstyles. Make crazy hair- it's not impossible.
those are just some basic tips. I can't really explain too much, and it's kinda hard to give tips when it's not colored. I hope this helped!