Here are the suitable words to fill in the blanks:

1. **festivals**
2. **at**
3. **On**
4. **after**
5. **wear**
6. **from**

So, the completed passage would read:

"New year is one of four important traditional (1) **festivals** in the United States. On New Year’s Eve, most people go to parties. At twelve o’clock (2) **at** night, everyone says “Happy New Year” and they (3) **wish** their friends and relatives good luck. New Year’s parties usually last a long time. Some don’t go home (4) **until** morning. Children usually (5) **wear** beautiful clothes and get lucky (6) **from** their parents."