Camo? Depends. When I was part of the green machine, a walk in the woods was camo everything, including putting on my war paint.
Mainly I now look at deer hunting (altho I have a friend that is a big time goose hunter, and I cannot describe all of their camo). One of the concerns HAS to be getting capped by another hunter, so I usually leave the ghillie suit in the back of the closet. And VA DOES mandate blaze orange for hunters in gun season.
I believe that turkeys see in color- and very well- but deer see outlines, and more importantly, they see MOVEMENT. Present a human shape upright, they alert right away- especially if it moves. Much of my hunting is now still hunting (ambush) with a rifle. Can't use a tree stand- and sitting or prone is out due to broomstraw that grows about 24 inches tall.
My compromise has been a collapsible chair, a roll of 550 cord, and 10 ft length of woodland camo pattern cheesecloth, 3 feet wide- and an orange vest. Pick my spot where I am not skylighted, good field of view, set up chair (shooting stick/s optional) and run the 550 cord between two trees about 3 feet forward of me, 3 ft off ground. Cheesecloth attaches to 550 cord w/ banker clips. I am now sitting behind camo that breaks up half my outline, I am lower than a standing man, it shields movement of my feet. legs, arms and rifle (in my lap) from view. I am also in the steadiest shooting position I can use- and pretty darn comfortable. Much better than butt on cold, damp ground.
Scent control is also important- note wind direction, use unscented soap on self and hunting clothes, can use masking scent- or just eat an apple (leave the peeling!
Have tried a sniper's veil, but except for turkey, has not really seemed to make a difference. If you can sit STILL, have had bucks walk with 20 meters of me while I was with bare face, ball cap, orange vest. Had a doe walk close enuff one day that I could have slapped her butt with my ball cap.
Each year, we have a few young hunters that sit with back against tree, doze off, and wake up to find deer looking at them from 30 feet away. I am convinced it was because when they are sleeping, they were holding still.