Your stuff is very smeary which probably means you erase a lot.. or just rest your hand on the paper... I suggest drawing softer until you have it how you like it then real fine darken the proper lines...
I suggested erasable colored pencils cause they smear less but still get shading like a pencil.. plus when scanned in as greyscale they look nice and clean. (You probably don't have any but they are real cheap
)
Look how comic artists do it.. they draw understructure before laying in the details, because if you get fixated on doing one area perfect it will be unbalanced in other areas.
(Personally I like using pen, I suggest drawing with multiple tools, sometimes you get a different style out of each. Different papers are nice too, sketch books have a bumpy texture and when scaned it shows up on computer... Unless you crank the contrast which makes the pencil smears show up more and the pencil lines too dark.. *This is why i recomend colored pencils they are less sensative to the scanners contrast and allow you more flexability.)
Example:
This of course was done with a wacom tablet, but notice how I did softer lines and shapes before laying in the detail.
Hair can be messy, leave some random lines or shape lines in it adds to volume when coloring or shading.
EDIT: I like your hydra BTW
