jmass, usually lens flair has to do more with the lens quality, its settings and the camera settings. Changing shooting angle can help. If you would please give us the Exif data for the shot. That's all the camera settings, lens settings, type of lens and camera model. That will tell us a lot about the shot and how it was taken. It's a good shot I like the blue cast to the snow and trees which imparts a cold feeling in contrast to the bright fire ball of the sun. The flair can be mostly eliminated in post processing. I agree with not clipping off the tree top. Another thought you might want to try next time is to take a vertical format shot along with the horizontal. All the trees present vertical lines and a vertical format composition shot might work out well. Another method you can use on a sun rise like this is to use a neutral density filter, something on the order of three stops, to take out some of the glair. That will have the effect of making the sun more of a round ball and give it, and the sky, more color. Overall it's a good shot, one that is worth doing again on subsequent day.