The basic factors to consider in regards to preservation of analog items, such as print photographs and documents, are:
For electronic items, be sure to routinely copy the items to CDs, DVDs, or external hard drives. Make more than one copy of the files and store in different locations. Be sure to migrate digital items when upgrading to newer formats.
*Avoid using plastic containers and sleeves that smell like a new shower curtain as these contain harmful gases (PVC) that will damage your items. Use storage folders or sleeves that contain polyethylene or polypropylene.
See the attached PDF for more information.
Online Resources:
Saving Your Stuff – American Library Association
Preserving Your Family Treasures – Library of Congress
Collections Care – Library of Congress
Digital Preservation: Personal Archiving – Library of Congress
Frequently Asked Questions about Preservation – Library of Congress
Caring for Your Treasures – American Institute for Conservation of Historical and Artistic Works (AIC)
How to Preserve Family Papers and Photographs – National Archives
Northeast Document Conservation Center – This website has helpful preservation tips and instruction
Personal Digital Archiving Strategies – MIT Libraries Institute Archives & Special Collections
Books:
How to Archive Family Photos: A Step-by-Step Guide to Organize and Share Your Photos Digitally by Denise May Levenick (Family Tree Books, 2015)
Your Digital Afterlife: When Facebook, Flickr and Twitter Are Your Estate, What's Your Legacy? Evan Carroll and John Romano (New Riders, 2010)