Be flexible. The most important thing to take to Nepal is a generous supply of patience. Delays and cancellations are standard practice in many locations throughout the country, so bring a good book or an interesting travel partner and settle in for the wait. Because its government is often in flux, fuel supplies can be delayed and stopped, which directly affects the bus industry.
Research before you go and when you're there. Online research and guidebooks can give you an idea about common bus schedules in Nepal, but chances are they won't be current by the time you arrive. Bus schedules change frequently in Nepal, so check with your hotel or guesthouse staff for updated times.
Visit travel agencies in Nepal. Most cities in Nepal will have at least one (and probably many) travel agencies who can give you bus schedules, book tickets, and help you choose which type of bus is for you.
Be brave. Even Nepal's hgih-end "tourist class" buses tend to be hand-me-downs from other countries. Because Nepal is a mountainous country, buses undergo high wear and tear each day. Tough conditions take their toll on buses, and it is not unusual to hear squealing brakes as they wind along downhill grades.
You get what you pay for. It is possible to take long bus rides in Nepal for less than a cross-town bus ride in New York City, but you may be sharing a bench seat with two other people and a crate of chickens. The difference between a $7 and $15 tourist class bus from Kathmandu to Pokhara is not significant, but the difference between the $7 ride and the $2 local bus ride could be enormous.
Be aware. Watch your luggage as it's loaded, particularly if it will be stored on top of the bus. It is not uncommon for men to ride on top of the bus during the journey, so reduce the possibility of theft by locking your bags. Carry any valuable items with you during the ride, and check your rooftop bags at every stop.
Arrive early. Many buses in Nepal do not have assigned seat numbers, so get to the bus stop early to avoid a long trip spent standing in the aisle or slipping off the edge of a crowded seat.
Hold your ground. When you get off the bus, taxi drivers will be waiting to take your luggage to their taxi. They can be aggressive, so be firm and do not allow anyone to take your bag. Be sure to negotiate a price with a taxi driver before putting your bag into his car to avoid theft.
Keep a sense of humor. Bus travel in Nepal can be frustrating, and a sense of humor will go a long way towards keeping you sane. If your bus is eight hours late getting in, laugh it off. Bring a good book, a portable music device, and enjoy the Nepali pace of life.