I realize not everyone can do this but we are retired. We took a 6 week vacation and visited family in 6 states. Besides the nice family connections, we asked them to pull out their old family photos. Of course, they said they didn't have any....ha. But, they discovered photos they had forgotten about and ones they thought were destroyed and useless with age. We brought back a treasure of photos and had them restored for FREE by a facebook hobby group called Restore and Color Old Pictures. They restored photos that were nearly impossible to see. One photo...when restored, I could identify the mother therefore, I knew who the newborn was that she was holding. One 3rd cousin I did not know, drove on snow covered country roads to meet us at our motel. She brought a box of 'goodies' including photos in those old curved glass frames. We took them out of the frame for picture taking and it worked great.
I think you get better results if you meet with relatives. NUMBER ONE SOURCE is relatives. But, I have also gotten photos from google search for name /photo. That is how I found Wiki Tree. Family reunions, funerals.... go with a good cell phone camera and contact people ahead of time to bring their photos. School year books, join facebook groups, etc. Good luck. I LOVE FAMILY PHOTOS.