I need a red packet.

我需要一个红包。

During the New Year, my grandpa gave me a red packet.

过年时，爷爷给了我一个红包。

We prepared a red packet for our teacher to show our gratitude.

我们给老师准备了一个红包，以表达感谢。

The money inside a red packet should always be new.

红包里的钱应该总是新的。

Parents would give the children a Red Packet which contains cash inside.

过春节，小孩子一定都很高兴，因为爸妈会给他们红包，里面装的可是钱呢。

Finally, an important piece of etiquette on receiving a red packet is not to open it in front of the giver.

最后，礼仪的重要组成部分是在接收一个红包时，不在给予者面前打开。