Post-processing
Always shoot in the RAW format, which will allow you to remove a lot more noise using Photoshop or similar editing software in post-processing.
However, when editing don't make your image too green. This is probably the biggest mistake made by photographers shooting the Northern Lights for the first time. While it's tempting to up the saturation, be really careful, and barely touch that slider. Your stunning images can very easily be made to look fake and ridiculous.
Advertisement
Coping with disappointment
Attempting to fix a camera on one of nature's most elusive sights doesn't come without hardship. Northern Lights-hunting is best treated like wildlife photography. Put yourself in the right place at the right time—and stay there for as long as possible—and you might get lucky.
That can be difficult in freezing conditions, so take a couple of other lenses with you, and perhaps try a time-lapse of clouds while you wait. If you do get lucky and see a decent Northern Lights performance, don't make the mistake of staying out all night trying to get a glimpse of them again; they only tend to peak once before waning.