Attach a paper wood-sander disc to your rotary tool mandrel and set it to low speed. Use this tool to sand the raised areas that are easy to reach. The paper disc is flexible enough that you don't run the risk of changing the shape of the detail but be careful that you don't slice into it with the disc's edge.
Replace the sanding disc with a padded drum sander attachment and use this tool to sand concave areas, inside cuts and flat raised surfaces. Don't press down or you could create a divot in the wood. Let the tool do the work. Use a drum cover slightly longer than the drum pad for extra flexibility.
Replace the drum sander with a bristle sander attachment to sand deep crevices and ornate curves. For very tiny areas, run a new bristle attachment against some scrap wood first to soften it slightly.
Use a cone sander attachment to sand the bottom of any circular pits and gouges. Use a very light touch here to prevent the wrapped edges from gouging the wood.
Finish with a very soft abrasive pad attachment or a mop sander, going over detailed areas delicately.
Wrap a large piece of sandpaper around lathe-turned designs, such as legs, and pull it back and forth. This allows the flexible paper to conform to the raised design to avoid accidental flat places.
Use a sanding block to sand flat raised areas. A regular fingernail emery board will work for very small or tight spaces.
Wrap sandpaper around dowels of appropriate sizes to sand in concave areas, inside cuts and curves.
Fold sandpaper around a credit card or a stiff piece of cardboard to sand in cracks and crevices. Making a sharp crease in the sandpaper, before placing the card inside, makes it easier to get deep into V-shaped valleys.
Mold a piece of sandpaper around the head of a cotton swab or the point of a toothpick to sand inside tiny bowl-shaped carvings.