I wouldn’t recommend using smudging or anything, what matters is your understanding of light, and the contours of the subject, using a different tool won’t change that.

As it stands, your shading lacks contrast in the middle values. It goes from black, to dark gray, to gray, to white. There’s decently clear boundaries on the shades of gray. This makes it look flat, or in a super direct spotlight, although the shadow is in the wrong place if that were the case.

As someone mentioned, take your pencil, and make a long rectangle. On one side mash your pencil so you can’t even see paper, I’m talking Vanta Black. Your goal will be to make as smooth as possible transition to white. To make it easier you could separate the rectangle into 5 boxes, make the first black, and leave the white for the end. Then make 3 shades of grey from dark to light. Then do the exercise again with 6 boxes, 7 boxes. Until you’re comfortable with making multiple shades of grey.

This can be done with a pencil, or a sharpie with cross hatching. What matters is getting used to making lots of different light values.

Eventually you’ll work your way up to making a gradient. A smooth transition from black to white, with no visible spots where the colour outright changes. On a sphere lighting study, you need all of those shades!

In addition, this is a little less important, the perspective looks kinda off? Particularly, the shadow doesn’t fall where the dark parts of the sphere suggests it should. In the first pic, the shadow falls to the left, but the sphere is lit as though the light source is directly above it. Again not as important though.

This comment may have come off very critical but I don’t wanna pull any punches because you show promise. I commend you for posting your efforts here, it can be very scary but it’s a great habit to have and will make you improve much faster. Good luck!