How is it going? Hearing that you have troubles making small talk with strangers in China, I'd like to offer you my advice following by many people.
Firstly, it is normal to feel a bit nervous when approaching to strangers. Everyone gets little shy first; after all, you don't know how they are like. The only way was to get over being shy and reach out to us. Secondly, Chinese people, especially young people, are general friendly, kind and enthusiastic. You can talk about almost everything range from sports, stars, movies to music. Thirdly, they are some sensitive topics such as age, weight and income, which should be avoided.