Nepal is a country that is deeply rooted in culture and traditions. Depending on where you visit you will find temples and monasteries on every other street corner. It would definitely help to know a few important things before visiting Nepal. For instance, you join the palms of both your hands and say 'Namaste' to greet people. This is the traditional way of greeting, however, a Hi or Hello will suffice too.
When visiting a temple or religious places, remember to take off your shoes before entering the inner sacred area of the temple. Also avoid having leather on you while visiting temples. In some of the houses too, you might have to take off your shoes before entering.
It is also important to note that you should not drink the tap water anywhere. Instead you can find mineral water bottles sold in the shops or carry your own water bottle.
Hindus consider cows holy. Therefore, keep in mind that beef is not usually sold or served in most of the places.
Even though the people in some of the places like Kathmandu, the capital city and Pokhara are dressed in a considerably modern way, in most of the rural areas, people are very traditional and conservative. You should avoid dressing scantily while travelling in these areas as well as religious places.
Nepalis usually eat everyday food with their hands, especially 'Daal Bhaat'. However, you will find spoons and other cutlery as well depending on the places you visit.
Most of the restaurants, hotels and eateries take extra 10-13% service tax on top of your bill, so you don't have to give tips. In some places they don't have the service tax so it depends on you whether you want to tip or not. Tipping is more common in adventure sports sector like trekking and mountain climbing and less in the hospitality business.
Sharing food with each other at the table is very common. Don't be surprised when people offer you their food.
Not all of the roads in Nepal are good. You will find potholes and mud, especially in the monsoon season with heavy rains. Remember to carry comfortable shoes with you.
The only official free day in the week in Nepal is Saturday. Sunday to Friday are official working days.
During some of the major festivals like Dashain and the Nepali New Year, most of the shops and services are closed. So plan ahead for these days.