Just duplicate the pics you've taken.
Use a large sheet of paper (A3 or so) in a medium colour as a background and prop the watch using a ball of blutack.
Make sure your phone or camera is steady by using a rest or even a tripod, or more blutack.
Dial shot should be directly in front, try to avoid reflections, rear and side shots are about the same as you already did.
Try to use natural light near a window and set your camera to macro (little flower thing in settings) if you can.
Don't let anybody try to remove the back cover unless you are sure that they know what they are doing.
It's not difficult but a gold case is extremely unforgiving of the wrong tools in the hands of the unskilled.
Good luck with it.
Cheers
Jim