Dogs get lost quickly and quietly: an open gate, fireworks, a leash pulled out of your hand. What happens next depends on what you do in the next few hours.
The first hour: do not leave the spot
The most common mistake is to get straight into the car and drive around the neighbourhood. A frightened dog usually comes back to the place where it lost its owner — but not immediately, more like an hour or two later, once the panic subsides. If you drive off, you miss each other.
Stay where you are, or leave someone there. Put something of yours on the ground — a jacket, a shirt — so the spot smells right. Do not call constantly, and do not run towards the dog if you spot it at a distance: a panicking dog runs away from anyone running, including you. Crouch, turn side-on, and call in a normal calm voice.
The first hours: who needs to know
Ring the vet clinics nearby — injured and found animals get brought there. Post in local building and neighbourhood chats: those are the people physically near you right now. Call shelters and the local animal control service.
Post a lost listing with a photo showing the whole dog in ordinary light. A studio portrait of a cute face is worse than a plain yard snapshot: people will search by outline, colour and size, not by the expression in the eyes.
What to put in the listing
Place and time, more precisely than "near the station". Breed or what it resembles, size, colour, distinguishing marks: collar, scar, odd-coloured eyes, docked tail. Always state whether the dog is microchipped, and your phone number.
Do not write a reward amount as a figure. It attracts not the people searching, but the people who call demanding money up front having found nothing.
Handling the calls
Ask the caller to send a photo of the animal in front of them, right now. Scammers send pictures taken from the internet, or refuse on some pretext. Never transfer money before meeting.
If the dog is microchipped
Give the chip number to every clinic you call. Any clinic with a scanner identifies the animal in a minute — provided the database holds a phone number that still works. If you changed your number and never updated it, do that now.
After the first day
The search does not end. Dogs are found after a week and after a month, often several kilometres from where they went missing. Repeat the listings, widen the area, and call clinics and shelters again every few days: the animal may have been brought in after your first call.