How can I help my sister?

Is she a biological sister? If so, then you really don’t care enough about her! If your sister is simple by nature and won't spend money randomly, sending money directly is the most economical option. Also, ask her what she wants and how she wants your help. Sisters, please communicate more.

If they are just relatives, then ask your parents whether they want to give you money or buy things. After all, it is also because of the courtesy exchange between the two families.

It turns out to be my brother, so you should call her from time to time and talk about study methods and so on. It is unrealistic not to pay her a meal in the same city and care about life. If she is not short of money, you can give her some pocket money when you see her next time during the Chinese New Year or something, and you can decide the amount yourself. Shenzhen's electronic products are relatively developed. You can ask her what she needs, such as a camera or a mobile phone. It's not expensive. Buy one and send it to her. She will definitely be very happy! You, my brother, have done a great job!