Nepal, Being a wonderful place to visit and explore, there are general things  that you better know before you plan to go. Its not very tough, but  as you land at the airport, unless if you've booked a decent hotel and asked for the transportation from the hotel itself(There are some 5-7 five star hotels inside Kathmandu ), the taxis will wait for you to take. Its similiar to all the other countries but Kathmandu as a city is not very fair as you'd expect. The roads are not nice and pretty dusty. However, You are  suggested  to stay inside Kathmandu for 1-2 days depending on the length of your trip.

You can see the Himalayan ranges from the plane before you land.(Hell thats a lot of beauty :) ).  During your stay in Kathmandu, you can visit few places, but basically these are of  cultural importances only and nothing much of natural beauty. THAMEL is the most happening place for tourists in and around Kathmandu. Visit there, get some souveniers. Plan to go around Patan Durbar Squar, Bhaktapur and Kathmandu Durbar square if you have enough time. Otherwise just go to Kathmandu and patan, these are pretty near(20 -30 min cab). Visit Pashupatinath, Swayambhu if u want to see some religion.

So, once you're done with Kathmandu, book a 4-5 day trip to Pokhara. Its heaven on earth. No much pollution. Stay at lakeside. You can book the hotel online. Plan hiking around Poon Hill, Dhampus or if you have enough time (more than 7 days) , Visit ABC(Annapurna Base Camp). But for this you must be there around the August - December. You can explore loads of tourist destinations online. There are lakes around Pokhara(Fewa Lake, Begnas, Rupa lake). 

Nepal is a must vist place. Hotels and other items will be listed later :)