3 Don’t Focus on the Lights
You can usually tap on the screen to convince the Camera app to focus on particular features and adjust the exposure when taking your iPhone photograph. This is almost always a bad idea when trying to capture Christmas lights. Tapping anywhere on the screen is likely to make the software try and focus on a particular light or set of lights, which often blurs things even worse and makes everything a bit distorted. Avoid trying to use focus features when snapping these pics, and instead just work on getting everything on the screen.
The exception is when you are getting really poor results and can’t really see anything but some lights in the darkness. In this case, you can try to carefully tap one of the dark areas of the screen. This can cause the app to adjust to that dark area and hopefully provide a little more clarity. Remember that you can also adjust the exposure manually to see if that will help.
A related and hopefully obvious piece of advice is to avoid the flash during these situations. It won’t help! Take a moment to make sure it’s turned off.