Does it break your heart to see those "lost dog" posters around town? You know you want to help, but maybe you just don't know how. Follow these tips.

[edit] Steps

If you see a poster, find out if there is a copy you can take. That way you will have the dog's picture and owner's contact information.
If you can't take the poster, record the name of the dog, the owner's name, and the contact info. Keep this information with you when you go on walks, in case you spot the dog.
Make note of where the dog was last seen, that way you can do some extra searching when you are in that area.
If you see see a dog that matches the description given on the poster, approach slowly, don't get too close, and call it by name. Do not make sudden movements or reach out for the dog until it has had time to sniff you.
Check if the dog has a collar with a tag. If the information on the tag matches the information you have, take the dog home and contact the owner. Or, if you have a cell phone with you contact the owner right away and let them know someone has found their dog.
Arrange a time for the owner to pick up their dog or for you to take it to them.

[edit] Tips

Look for the dog whenever you are outside.
Read the poster carefully so you get all the details.
If the dog's collar doesn't match the information you have, call the number on the tag.
If the dog has no collar take it to the local vet's office.
Carry dog treats with you.

[edit] Warnings

Be cautious when approaching dogs. It's possible that it the dog has rabies.
Do not try to force the dog to come with you. If the dog won't come, call the owner and let them know you have spotted their dog.
Don't run after the dog, this will frighten him/her and they will run faster or attack.