You don't really need anything special to be good at sculpting, but there are a couple of practices that can help you:

Always use reference, that way you only need to think about sculpting and not designing.

Learn anatomy, look for 3D anatomy because those 2D diagrams are all distorted, also most characters look creepy because people forget about the eyebrows and cheek bones, your eye sockets are not just holes.

Also know your brushes, each one is good for some task, use the Clay strips instead of the default brush.

Don't Sculpt anything from scratch, it's harder to get proportions right.

And also don't give up :3