Real gold/platinum jewelry will not alarm, unless you're wearing as much of it as Mr. T. Keep it on, including the watch if it is small. If you have a big watch, put it in your carryon for security. Costume jewelry should be placed in your carryon from the start.
The only electronic device that has to be out on it's own is a laptop. You can put all your other electronics securely inside your carryon bag.
Best bet for security is to empty all pockets into your carryon before even approaching the checkpoint, and take off your shoes and metal-buckled belt, too, if you can. The only thing you should be carrying on your person is your ID and your boarding pass.