Luggage and bags:
Hotels in Fraserburgh don't have lifts. You need to be able to carry your bags up at least 1 flight of stairs yourself.
Clothing/Shoes/Weather Gear: Never forget to pack a waterproof coat with a hood. A brolly isn't much use as it can be really windy.
Toiletries and Medical Supplies: Good range of chemists in Fraserburgh so you can always buy anything you forget.
Photo Equipment: A camera is a must. Plenty of beautiful landscape photo oportunities.
Miscellaneous: Summer doesn't last long here (blink and you might miss it). Be prepared for any weather even if you come in mid summer.
Waterproof & windproof clothing essential. Wellington boots if you are going pond dipping. Layered clothing especially in summer - you can always add or take away
Photo Equipment: A good zoom is essential as are binoculars