Firstly, if you can find the tooth and it is clean, put it back into the socket yourself. If you can’t put it back, put it straight into a cup of milk or keep it in your mouth.
Don’t panic.
Do go to a dentist or hospital as soon as possible.
Do take painkillers if you need to, but don’t take any medication containing aspirin as this can cause the bleeding to get worse.
Don’t hold the tooth by the root, as teeth are surrounded by fragile ligaments which need to be kept intact if the tooth is to be put back in.
Don’t clean the tooth with disinfectant or water, or let it dry out.
Don’t put aspirin or clove oil on the wound.
The sooner the tooth is replaced, the better the chances of success. If you have not managed to do it yourself, the dentist will put the tooth back. They may use a dental splint to fasten the tooth against the teeth on either side. In most cases this is successful, and once the splint is removed the tooth is stable. However, you will almost certainly need more treatment in the future.