Take a piece of paper and bend it over the watch. Ideally you want to have a neutral colored sphere arounf the clock, with only one opening for the camera lens. Try to get as close to this as your background and environment allow, to eleminate all abjects that your clock could reflect. You will need a reasonably strong lightsource (flash) too, because the cover will suck up a lot of light.
Easiest setup for details: Just take a piece of printing paper (or tape 2 together if you need more space). Bend it over a surface and tape it down, so that you create an arc. Flash or lightsource over the paper. Some nice background behind the arc, watch under the arc, and shoot it through the remaining opening. For larger setups it gets tricky, but diffusing all lightsources will help
If you don't move, and especially if you're close, you will only be abled to get a small part sharp because the perspective of the car changes. If you want the whole car in focus, you gotta stay in the same position relative of the car aka you need to shoot from any other vessle, moving the same direction and speed as your subject. If that's not possible take a tele and get a good bit of distance between you and your subject. That might help