Great point Bufalobob. I was fortunate enough growing up to spend countless days with a good friend of the family learning how to hunt. We mostly hunted Blacktails in the timber and clearcuts here in Skagit County and if you've ever looked for blacktails, you know they can be hard to spot. He taught me a lot over all those years and probably the best thing he taught me was how to spot big game animals. I asked him one time when I was probably ten or eleven to tell me how to see animals in the wild. He said "Look for things that don't look like a rock, a bush, or a tree". His answer was oversimplified a bit, but profound. In the twenty-five years or so since that advice I've learned that for some reason - to my eye - deer, elk, bear, antelope, etc., have looked somewhat "unnatural". I don't know if that makes sense (it's early and I'm only on one cup of coffee) but when you break down the body parts of big game you start to realize that a horn doesn't look like a tree branch, a deer's backline really doesn't look like a log, and there is nothing that I have ever seen in nature that looks like the dark eye of a deer or elk. As was mentioned earlier most of these slight differences between big game body parts and other "natural" objects can only be seen consistently at distance with GREAT OPTICS. If you have to pinch pennies (we're all on a budget) DO NOT do it on binos or spotting scopes. You can't shoot an animal you don't know is there and 99% of the time the easiest buck to see is the smallest one.
As for a glassing routine, I've always approached an area looking for movement on the fringes first as spooked animals don't stick around for long if they are close to cover. Then I start to pick apart the areas that look like they should hold game. Look for areas close to cover like along creek bottoms and on hillsides with reprod. Take your time - in my experience it takes about twenty to forty-five minutes or more once you are into an area for things to go back to normal operation. Yes, I have snuck into areas without being detected by big game, but something always knows you're there and alerts the surrounding area that "something" has changed. You'll have a better chance of seeing game if you sit tight for a while.
My last advice is, if you are able, learn to spot game yearround. Animals in the spring and summer are generally more out in the open and are usually a brighter color and easier to see. If you continue to scout and spot them, your eyes will adjust to them as they begin to blend into their surroundings more by darkening their coats and you'll be more likely to pick out those single body parts as they become a bit more sneaky. DON'T LOOK FOR AN ENTIRE ANIMAL...YOU WILL RARELY SEE ONE. I don't consider myself an expert spotter but I did learn from one. Kind of sounds like a Holiday Inn express commercial?! You all have a great day - I'm going shooting.
Ignorance is bliss...unless you're aware of it.