Access is easy via a road that leaves from the Viking Cafe. There is a fee per visitor to proceed beyond the barrier (around 800 ISK per person) and you can then drive a quarter of a mile towards the ocean with the dunes on either side. There's parking on the left. Leave your car and head off on foot. There are toilets by the cafe, and it's a lovely spot to warm up (with one of the most expensive cups of coffee you will ever buy!).
Arrive early and leave late. Stokksnes is a beautiful, iconic location, and as such, it attracts a *lot* of visitors, especially photographers. On our morning at Stokksnes, we arrived several hours before sunrise and effectively had the place to ourselves for a good two hours. When I finally turned away from the view to head back to the car there was a phalanx of Japanese photographers, all lined up in a neat row. The daily expeditions had begun.
Be extremely careful where you walk. The dunes at Stokksnes are absolutely beautiful, with pale beige grasses gleaming like beacons on top of the inky blue-black sand. You can find some gorgeous leading lines in the water as it flows back into the ocean as well as a number of dead calm pools that are perfect to catch reflections of the mountains in. HOWEVER, footprints absolutely ruin the purity of the composition. If you do happen to be first on the scene in an unspoilt area of the dunes, start from behind what you intend to capture and walk towards your shooting point to minimise the chance of picking up your own trail.
If the main body of dunes is somewhat tracked out with footprints, try heading to the Western side of the road where they are less travelled. You should still be able to put together a composition that works with the added bonus of not having to spend half an hour clone stamping out all the photographers & tourists.
Even though the dunes provide first class foreground interest, consider heading right down to the beach. Whilst you should anticipate sneaker waves like anywhere else on this coast, the beach is long and relatively flat, so the water recedes gently and creates some great opportunities for reflection shots. I never had time to shoot from the beach on this trip but will definitely make it a priority if I'm in the area again.
Don't miss the Viking Village. It was built as a film set for a movie that was never made in 2010 but will be the scene of a new film by Baltasar Kormákur called Vikingr that is expected to begin shooting in 2019. The village can be found a short walk from the visitor's centre, and on a clear and windless day is a great location to fly your drone, as the shallow waters in front of it make for some great reflection shots.
Lens choices. The mountains are massive here and seem to go on forever, so you don't want to be too close to the subject. I'd recommend a real wide angle (14mm or lower) as a basic first choice, but I tended to opt for taking panoramas to get the whole scene captured in the greatest detail. I set the tripod to be as low to the ground as possible in order to capture as much of the foreground interest as I could, and then carefully rotated it around its fulcrum whilst maintaining consistency in the horizon line. I used my 50mm prime lens for this and found that around 8 or 9 images were required to capture the scene. This is more work in post-processing but it gave me several large format images of over 100 megapixels and way more clarity than with a single shot from the wide angle.