I opened a shop with 2 yuan money. It's all small things. Children often wait for customers to steal. what can I do?

Observe more, see what children like to steal, be strict with some children who always steal, and tell some stories of stealing and being killed to your suspected children, so that they are afraid. If not, find two more people to have a look. If the thief is caught, send him to the police station at once. Before sending it to the police station, ask him why he stole it, and then bypass him and ask his parents for money.