1-SORT all your photos in one place and ask others for photos that they may have that you would like to have a copy.
2-SCAN as many photos as you can! This can be a very long process if try and do it on your own (like 2 minutes a photo) but if you hire a professional (like me) we have high speed scanners that also enhance photos to make them look as good as possible.
3-SAVE the digital images in a variety of places. DO NOT just leave them on one computer to your phone because if it is lost, stolen or destroyed you could lose everything. I personally back up to an external hard drive, an online automatic backup and to different photo sharing websites.
4-STORE the original photographs. DO NOT throw out the actual photos after they are scanned (at least not all of them) because those are still the best quality of the photo. Ideally, they should be kept in archival quality boxes. If the photos will boxed and placed in storage, at least kept in plastic, sealable storage containers that will keep out any water or pests.