All the above.
But that being said, I read years ago, about a guy hunting in Central America,
with an Indian guide, and he watched this guide walk up to about ten feet of a deer, before it noticed him. He said that deer, will graze, for about ten seconds, and then look, and around, and if nothing is moving, or there is no dangerous scents, it will go back to eating, and repeat the process. So I tried this out, in the Big Cypress, years ago, when I was in my early 20's,. A friend and I were down at My Dad's cabin, and we were walking in a prairie area, when we saw a doe, and a fawn. So I told my Buddy about the article I read, and said I was going to try it. Well darned it didn't work. That is until the little fawn looked up before his Mama, and saw me take a step, and at the instant, Mama swung her head and stared directly at me. I froze, and she did the look away, and then suddenly back again bit, and finally I just clapped my hands, and they took off.
But before Jr. spotted me I did get to within about thirty yards, of them, and this was in the open. You just wait till they put their head down, and take slow easy steps, and count to about 8 seconds, and then stop, and be perfectly still, slow your breathing so there is minimal movement. Then just repeat. But this only works well on a single animal. Like Jr.,if there are more than one, one might look up at a different interval. Again, there were no leaves, just grass, and it was mostly green, and the ground was damp, so noise is a factor to figure in also. Just something to consider, to the above advice, but I do know from my own experience that it works. Just be aware of the wind, noise, and movement, and such.
Wayne