Nepal has numerous cultural practices that are unusual to foreign visitors, so being aware and following them, when you can, will add so much to the whole experience. In the busier tourist areas, like Kathmandu or Pokhara, there is a high degree of tolerance towards visitors, but when we head further afield and away from these places, you should be sensitive to local customs. For example, shaking hands is not a common form of greeting; instead make a great first impression by pressing the palms together in a prayer-like gesture and saying Namaste (nam-ast-ay).
A few social conventions we recommend to follow are:
Women should dress conservatively and keep shoulders and legs covered (a good rule of thumb for Asian countries is have your elbows to knees covered)
Permission should be sought before taking photographs, particularly at religious sites
Public displays of affection between men and women are not seen as appropriate
Footwear should be removed when entering houses, especially kitchens, or shrines
Seek permission before entering a temple, and do not take leather articles inside them
Remember not to point with a single finger but use a flat extended hand especially to indicate a sacred object or place