One of the most essential accessories in my kit bag is a compass. It has travelled the world with me to some amazing locations over the years.
I use it when scouting locations to see where sunrise and sunset will be and is particularly useful when skies are dull and overcast. With the use of the compass you will then know if a location is good for sunrise or sunset light.
For the UK a sun compass can be used which tells you where the suns position will be throughout the year, great for location finding and advanced planning.
If you have a smartphone there are apps for this too, though I still stick to my trusty battery free simple compass which I`ve had for 20+ years.