1. They're not as green as they appear in photos
Don't get me wrong. The Northern Lights are spectacular. They dance and shimmer across the sky, twisting into all kind of shapes. They're just not as 'luminous' as they appear in photos. Adjust your expectations to a kind of 'grey-green' and you won't be disappointed. (And don't worry, they'll still 'pop' in your photos.)
2. Practice taking long exposure photos before you go
I know my way around my camera pretty well, but when the Northern Lights started swirling around my head, I was caught short. By the time I'd fumbled around in the dark, adjusted exposure times and composed my shot, the lights had moved on. If I'd practised at home it would have been second nature to me.
3. Keep an eye on aurora forecast websites
To be honest, what kind of display you see – and whether you get to see it all all – is in the hands of the Gods. And having booked your trip months in advance, you've pretty much got to accept what you get. Having said that, Aurora forecasting websites like NOAA's Planetary KP index and Space Weather forecast can give you an indication of the level of activity and expected peak times – information well worth taking into account when you're standing on a frozen lake in sub-zero conditions.
4. Hostels and hotels supply warm clothing
When you book your accommodation, check whether your hotel or hostel supply snow boats and warm clothing. In Abisko, in northern Sweden, most did. If I'd known, I could have left my snow boots and ridiculously bulky jacket at home – and enjoyed a more comfortable flight there and back!
5. Pack hand and feet warmers
Available at any outdoor shop, either disposable or reusable, these are must-have items when you're standing around, north of the Arctic circle waiting for a fickle natural phenomenon to show. They don't just warm your extremities, they raise your spirits as well.