Walk round your local area - ask people if they have seen your pet, leave your phone number.
Create a poster with your pets picture and your phone number. Put them up round the area and hand them out.
Call local vets during the day (and vet emergency services in the evening).
Contact the local pet rescue centres and animal shelters.
Give copies of your poster to vets, pet shops, groomers etc.
Give copies of your poster to other dog walkers in your area.
Search the web for local pet lost and found websites. Add your pet's details.
Don't give up - keep looking and stay positive.