Editing motion paths accurately

This is how I do it.

1. Make a copy of the object or image.
2. Move the copied image to the correct position
3. Create a motion path for the copied image
4. Note the X and Y starting position of the copied image. 
5. Create a motion path for the original image.
6. Add the noted x and y coordinance from the copied image's motion path and add it to the destination position. 
7. Delete the copied image.

If you need to move it along more than one path, Follow the steps above again. But make the now motion path have the same starting position as the ending position of the first path. I find it helpful to keep a log of the path positions as I go. 

An example of how I use this. I currently have a 7-page document. stitch together jpg images of the pages into a grouped object. Then I use this technique to move the document to the desired position as the narrator talks. 

Hope this helps!