Well nice use of shapes, especially on the squirrel. Your shading is blocked out which for a sketch and practice is exactly the approach you want. Most of what I'm going to say is just me trying to show you how you did very well and only a slight shift of perspective will help you see where you need to focus on improving. I hope to show you that. There are many approaches to drawing, you have to figure out what works best for you. Hair should be approached the same way. get the whole figure worked out made out of big shapes then proceed to smaller shapes, like shadow shapes and then other landmarks within the figure. If you're drawing long hair on a persons head you'll want to draw hair in "clumps" the Head of hair will be divided into chunks and those chunks will be "worked" to look more like the style you're going for. A stumbling block for people learning to draw in pencil is we think we're drawing objects. Look up Observational drawing, it teaches the artist the difference between perceptual drawing vs drawing "things" or "objects". drawing what you perceive instead of objects will help you out a lot. 1) there's not much fur to draw here. even though you know the animals have fur. 2) remember you're not drawing animals with fur your drawing shapes and tone (light and dark) and utilize the direction of your pencil stroke as well as the thickness. Some shapes you wont want any visible pencil strokes just a flat tone, other times you'll want clearly to see pencil lines going in a direction, sometimes uniform sometimes not, it depends on the texture you want to create. 3) what you drew gives a sense of fur, you did well.