There have been a couple of questions in the forum about where to go in order to see the Northern lights/Aurora borealis. So in order to not have to repeat myself, here is a short guide on how to see the lights.
While I do like to keep my anonymity on the forum, I live enough north to be able to see the lights every now and then, and I can understand why people travel to see them, they are beautiful. And when I was at university, I did study related subjects so I have a bit of understanding for how they work.
The most important thing to remember is that the lights are a natural phenomena. They might show up, or they might not. There are no guarantees. But knowing a bit about them can increase your chances.
Are there Auroras? The light form when charged particles from the sun enter the atmosphere. There is not a constant stream of particles, it varies a lot. Monitoring solar eruptions means it's now possible to give a decent prediction of the lights, there a number of websites and apps available. Find one you like. Just remember that the predictions are nowhere near perfect. If the lights show up, they form around the so called the Auroral oval, at around 65-70°N. The stronger the lights are, the further away from the oval they can be seen. The solar activity is tied to the solar cycle which is a roughly 11 year cycle, and we are probably very close to a peak.
Clouds. It doesn't matter how beautiful the lights are if the sky is covered in a thick layer of grey clouds. Booking a trip after looking at the weather forecast is rarely helpful as the weather probably will change. But some locations are cloudier than others and that can have a huge impact on your chances of actually seeing the sky.
Light pollution. An obvious factor that can be overlooked. The best place to see the lights is somewhere dark. If the lighs are strong, it doesn't matter if you're standing next to a streetlight. But if the lights are faint, location can be the difference between seeing a great show and not seeing them at all. And sometimes a small distance reduce the light pollution a lot. The moon can also have an effect, so for the optimal trip look up the moon phases before going.
So, what is the best place to see the lights? Good question, I'm not going to name a single place the best, because no place is the best. But some might in general be better than other. Finding a place at around 65-70°N is in general a good idea, the lights can be seen outside those latitudes, but the closer you are, the better your chances are. That is also the reason going to Svalbard to see the lights is a bad idea, it's too far north.
Finding a place with a low chance of clouds is also good. And one of the reasons that Iceland and the Norwegian coast has some problems. The gulf stream brings a lot of warm water to the north atlantic, some of that water evaporates and then condensates as clouds. The Scandinavian mountains increases the cloud formation along the coast and keeps the clouds there. Going to Iceland is not a bad idea, it is a great place to visit. But if the northern lights are the main goal, I do not recommend Iceland.
Then there is also light pollution as well as looking at what fits your trip in general and other considerations. Northern lights tours are often marketed in many towns in Northern Europe. They can be a good option, as they will look at the cloud cover and usually find a place where the lights are visible. But be aware that they can sometimes drive very far, so be prepared to spend many hours in a van.