As I've said many times before, collage is dialogue. Image speaks to artist, artist listens, interprets, talks back to image with scissors and marks, reinterprets and so on, until the conversation is finished.
It takes going through a lot of images and pulling only those that strike a chord. It's a very "of the moment" kind of thing. The rest get tossed. Or sorted and saved, if they have potential. After a while, the very act of tossing and saving becomes instinctive, bypassing conscious thought and becoming more an extention of the limbs than an activity of the brain.
That's what I'm doing today. Weeding my garden. Thinning the stack. Out with the old to make room for the new.
Happy New Year!