1. Nepal offers one of the easiest visa services for nationals other than Indians (It is much easier for Indians actually :) ). You also have an option of visa on arrival; properly filled up visa application form and a passport size photograph is all you need.
A single entry visa of 15 or 30 or 90 days costs you USD 25 or 40 or 100 respectively. All major currencies are accepted at the Kathmandu Tribhuvan International Airport.
2. Indians do not require a visa to enter Nepal. In fact, Indians can even travel to Nepal holding a valid passport or a voter ID issued by the Indian government.
3. Upon arrival; you need to fill the immigration form with basic information required.
4. Before entering to the luggage belt area, your hand baggage is scanned. Luggage collection can be somewhat frustrating at times. Since it takes little longer for luggage to arrive on the belt.
5. Make sure to keep your luggage tag with you properly, since it will be cross-checked and collected before you exit from the airport.
6. You can also enter Nepal by road from India. Either from Darjeeling side which is actually a quite longer route and not really suggested. Entering from Gorakhpur can be an easy option to enter Nepal, which brings you to the first town of Nepal Sunauli from where you can easily get a bus to Pokhara.