The earings on this character is a really nice touch and are well done.

About the only thing you might need to do with this drawing is slightly move the muzzle to the right as it is a bit off centre. Besides that the drawing is very well executed.

pen

It is really impressive that you managed to do all of these drawings with pen and it is no small effort to get things done correctly the first time as you have done as for most folks it would take a lot of drawing and erasing to get to where you are.

I would definitely invest in a good pencil, preferably something made in the United States, as you will get good results from them. The Chinese made pencils are a pain, and the erasers on them are the worst. Stuff made in these United States or Europe is the way to go especially when it comes to art supplies.