I have this dry, thick, and rough skin on the top of my foot. It's also a little darker than the rest of the skin. How can I get rid of it?

Try moisturizing it. It is a little odd to complain of rough skin to the top of the foot as opposed to the bottom of the foot and hence, it may not just be "dry skin" you may have a dermatitis of some sort. Therefore, if moisturizer does not work visit a podiatrist or dermatologist to have it looked at.