Hello! Sister here. Some advice I can give would probably start off with the structure of the piece. The head is off-centered, so something that helps me personally is to draw out the lines of the face. One line for it's length, the other for the width. And smaller lines for details such as the eyes and mouth. That way, if you follow your lines it will end up being more centered.
The second critique I can give is the weight of the lines. All of the lines seem to be close to the same width and opacity, including the detailing. For traditional art, have a very sharpened pencil. I mainly use a mechanical pencil personally. This way, you can control the thickness and hardness of your lines, making it have a lot more depth and detail.
And the third and final critique, is your use of angles and lines. Most of your shapes are very round and circular. This can be fine depending on your style, but given this piece looks to have more detail, that means you should also do more sharp shapes and lines. Such as triangles. One place that would have been good, is the chin/jaw of the creature. It would have made it look a lot more mysterious and powerful. If you have a hard time getting the lines right, I suggest looking at references. To be honest, just always look at references. It helps way more than I would have expected.
I think that's all I'll give now, you did a really good job regardless and I really enjoy how the creature looks! It mainly comes down to execution and techniques that you can learn to make it when better. Hope you have a good day and this helped!