Please help correct the mistakes

Dear Mark,
Glad to hear from you. I’m very happy that you’re interested in the ways that we Chinese high school students celebrate our graduation.
In China, the college entrance examination is really important, so students will relax themselves a lot after it. Many of them have parties and hold great feasts inviting their relatives and classmates. That create a relaxing atmosphere but really cost a lot of money. Some of them go traveling alone or with friends. They travel to places they dream of, and even go abroad to experience life.Traveling is good but sometimes can be dangerous. Also students write about their best wishes to friends. We feel warm at these notes but sad to leave high school forever.
I think the more meaningful way of celebrating it is to do some social work. Social work can develope your overall abilities and also promote awareness of helping others. It also indicates that you are an adult and take your responsibilities well.

I know it is not very good, but let me know my mistakes, and thank you. If you have good advice, please tell me. I would like to correct my mistakes and do it better.