I've noticed a lot of enthusiasm for taking pictures of Christmas trees and outside lights among people I know and as everyone has discovered, it's hard to get a true rendering of the softly lit scene. So I've come up with a couple of hints which may help, hints I've learned after years of trial and error, reading advice from experts, and just plain luck.
One technique which will always bring up a clear photo of a Christmas tree is to use flash, but by using the flash you lose all the ambiance of the lighted tree. There's very little color and the picture is as you'd see it during the day with no lights on. That's not what we want. Like this
If you take the picture with no flash, the ending picture normally has some blur, like this:
Now what's the best way to do this? My advice is from an amateur perspective, not a professional who has all the bells and whistles, lens, meters and tripods.
If you have a pocket sized digital camera i.e. a Canon or Lumix or Kodak or any of the many on the market there will be a dial near the shutter button to change the settings so that the camera will know what you're trying to achieve. I've had good luck with the night scenery or candlelight setting on my Lumix and Canon. It also works with a digital SLR as well. But here's the main thing you want to do in conjunction with this setting, put the camera on something stable and then push the shutter button. I have been carrying around a wooden kitchen bar stool that we normally sit on. Spending several hundred dollars for a tripod is not something most of want to do and using what you have can work well.
Put the camera on whatever you have, make sure the flash is off, check the scene in the viewfinder, push the button and then take your hand off the camera. Most of the time the shutter will stay open for a few seconds to record the scene. Leave it alone until it is completely finished. Try this a few times until you find the best way to keep everything steady and you'll be surprised how much better your Christmas lights turn out.