Filtering by meta data
An effective, seamless way to filter and sort photos is by using their own meta tags. Without any change or added work, photos can provide data such as date, location, people that appear on they.
Some apps, like Apple's Photos, offer filters for those meta tags. I can easily find pictures taken in October 2011, for example, or that were taken in some city. I also can filter all pictures in which my sister or a friend of mine appears.
I've been in Apple ecosystem for the last six years, now I'm trying to move out to Linux. One major trouble I'm facing is finding a photo manager that has this kind of filtering/sorting. They are incredible handy, so much that I acutally don't care that much to folders or file system structures anymore. I'm a little surprised that there's no Linux app that offers the same functionality (as far as I can tell).