What should I do if the hook doesn't stick to the wall?

You can use the egg white in the egg shell to increase the viscosity of the hook, apply it to the hook and the wall, and then stick the hook to the wall when it dries slowly and press it hard. After 24 or 48 hours, the hook can be firmly stuck to the wall. However, before applying egg white, it is necessary to wipe the wall clean and keep it smooth and flat, and then apply egg white after the water on it is dry.