Well as long as they are in a bag, easy way for me is to feel them. Looking for a key part that no others have.
For example, the tsum tsum blind bags, if I was looking for stitch an easy way for me is to feel for his little space ship. On display boxes or bags, it normally tells you who is in the bags and what they look like.
Another example is lego blind bags, if there is a swordsman, I feel for his sword.
Your thumbs get a work out, but I rarely get doubles with feeling blind bags. Hope this helps.