-Strong evidence that shows the purpose of the visit.

- Sufficent bank balance and property that shows tie to Nepal

-Invitation letter who is inviting

-Letter from Internation School and Department will be great

-Copies of I-20s passport and Visa

-Other documents as much as possible.

It may not be logical if you have Graduation in Dec and your parents come in March April- might have problem in Port of Entry unless your parents are able to show some other decent reason of visit.