>>1712898You certainly have some thickness issues, mainly in the hair. The right side of her hair is thicker than the left for the most part. The hands are also thinner than the skin lines, most notably in her left hand holding the skull.
However, the bigger issue is just how you use your nodes. You are using too many in the hair and creating a lot of kinks, especially at the front of the hair and the intestinal twintails. You need to start with the minimum nodes you need. For hair, only add nodes at the tips and give all the nodes handles. Then play with the handles until the lines are consistent and the hair is smooth. If you need to add nodes, then do it after you have messed with the handles.
Here is an example of what the nodes should look like for hair, in general.
