Looking: Look through binoculars and only focus on the "full" picture. You often are expecting to see a full animal. You scan quickly, often times only hitting open patches, and proclaim "no animals". You either get up and move on or fidget around. If there is no rest for the binoculars (trekking pole, tripod, etc) then you are looking.
Glassing: Look through binoculars and only focus on small pieces of the sight picture. Every single thing gets dissected; every bush, tree, rock, etc. Once you confirm that there is no discernible animal do you move the binoculars a small fraction and repeat the process; always keeping 75-80% of the area that you just dissected in your view. You do only look for a fraction of an animal. Once you have glassed everything, you do it again, again, again, etc. Animals tend to "magically" appear out of nowhere. Found this to be true with bear (black and grizzly), sheep (Dall and desert), whitetail (regular and Coues), mule deer (Rocky Mountain and desert), axis deer, elk, javelina, mountain lion, moose, caribou, etc. You'll get more opportunities with this approach but some animals will still slip through the cracks.
It is easy to say to look for part of an animal such as the inside leg (color differential). The hard part is finding it on your own the first time. But once found the first time, each subsequent one becomes easier and more natural. Over time you will build an internal "database" and makes finding animals much easier and quicker.
It is easy to notice the difference between someone glassing and someone looking. Doesn't matter if they are sitting next to you or are on a ridge over. Their actions and body language are dead giveaways. I'll keep tabs on folks to know if I should glass in their direction (lookers) or if I should exclude that area (glassers). I know the lookers will likely miss animals where the glassers will likely have found them.
