Start preparing now for your delivery. You'll need some white gloves, a 35 megapixel full frame 35mm digital camera with macroscopic lens, a professional photography studio, a laboratory grade microscope, a stethoscope, and some Pantone color panels.
When your watch and phone arrive, carefully photograph it on all sides under professional lighting. Print the photos and examine them under the microscope--slight variations in the reflected light will highlight areas of concern. Then write yourself an iOS app to fill the screen with solid colors and nothing else. Compare those colors against the Pantone sample under good lighting. If you find any discrepancies, be sure to make a post a video to YouTube complaining about Apple manufacturing.
For extra credit, drop the phone from various heights to figure out what kind of impact it can take before it cracks. If that doesn't work, grip it with both hands and twist it until it falls apart (bending has already been publicized). Don't worry about destroying your iphone--your YouTube video will make enough from advertising to buy a replacement.
Alternatively, test water resistance. IP68 means the phone should survive for 30 minutes at 2 meters depth. Test it! If it only lasts 29 minutes, that gets you more YouTube publicity!
Seriously...do nothing! Nothing at all. When your phone and watch arrive, don't "look" for anything. Just start using them.