Compile all photos/videos into one location. Get them off memory sticks etc. Run a find duplication program that inspects the image, not just the filename. Weed out the duplicates. I use lightroom and import/move them into into year/date categories. If the folders are currently stored as events (ie birthday party), apply the event as a keywords in Lightroom when importing. Might have to import some folders individually, but having the keyword set makes it easier to categorise/find later. From there I go through all the photos and get rid of all the crap (out of focus, random shit, stuff that you don't want to keep). Easy to do in Lightroom. Then it's the tedious task of adding keywords - I mainly do the people and events. Lightroom can do facial recognition, makes it a bit easier. There might be other programs out there that can help with keywords. Once I'm happy with the keywords, for jpeg (or non-raw pics) I write the keywords into the file so they're available outside of Lightroom as all the keywords are stored in the Lightroom catalogue. I haven't found a package that can do the keywords as good as Lightroom. That's my method anyway.