When to go?
Of course the Northern Lights are one of the main attractive for visiting Iceland, however, it is also one of the most unpredictable phenomenons. These lights are by no means easy to catch.
There are lots of factors that intervene such as season, weather, location and definitely some amount of luck is involved.
For catching these colorful wonders, the recomendation is to go in the winter season from November to Febuary. These months have the longest darkness periods. However, you have to take into account that between these months there is also stormy weather where clouds can block your view.
Your chances of seeing the lights are higher if you stay for longer. In my case, unfortunately I was unable to see them (...sniff sniff), I stayed 4 days which was not enough. The recommended length is 7 nights. However, there are people who are able to see them on their first day, as mentioned before, it's pretty unpredictable ;).
We could see our odds of seeing the northern lights through the Aurora forecast from the Icelandic Meteorological Office. This is a very useful tool where you can see a map in real time of the areas of clarity, (aka no clouds or light pollution) where it is most likely you can see them.
For our stay, we arrived to Gretir Guesthouse, which was quite pleasant. For Icelandic prices, it was a pretty good deal. It has a self check-in service, the rooms are very charming and it is located in Laugavegur, Reykjavik's main shopping street.
The only critique I would make is the fact that you share one bathroom with about 5 more rooms. If you are lucky and all rooms aren't occupied, it's pretty good! Otherwise, some organization will be needed.
While I was in Reykjavik, I mostly cooked inside the Airbnb, however, I did go to Fisherman where I had this delicious Artic Char in Bernaise sauce. It was excelent! It is one of the best ranked Seafood restaunts in Iceland. It is a bit out of the way from the center of the city, but recommendations led us there and we were not let down. It is also more affordable than high end places such as those in Laugavegur street.
For more info about where to go eat or to have a night out check out Visit Reykjavik for a wide selection of places.