Sanding isn’t hard when you’ve got a flat surface, because the sanding pad or sandpaper you’re using is also flat.
It becomes a little more difficult when you’re working with a round surface.
But slightly modify your technique and it’s no problem.
Using a utility knife, cut the sandpaper into strips. Then use the sandpaper strip like a polishing cloth on a pair of shoes. Move the paper back and forth so that it contours to the shape of round objects.
If the paper tears, simply take some duct tape and apply it to the back of your sandpaper.
The duct tape actually reinforces the sandpaper.