Trigger speed. If less than 1 second, you can have it on a trail and even place it perpendicular to the trail without missing much walking game. For slower triggers speeds, those cameras a best placed in areas where deer might loiter...corn/protein feeder, water source, mineral site, etc. If slower trigger speed camera is placed on a trail, try to aim it down the trail to capture the game. Best to face cameras north and south to avoid morning/evening sun glare. Trim tall grass and vines in front of camera and make sure there are no overhanging branches nearby as well. Otherwise, your night pics will have a 'white out' effect. I use the low glow infrared cameras and I like to place my cameras several feet up off the ground and have them at a downward angle. Deer seem to notice them less the farther from the ground they are. Hope this helps some.
"Few men...will pass up an antlered buck for the better-eating doe standing beside him. And fewer still, having shot an exceptional buck, will leave that great rack in the woods and pack out only the meat." John Wootters. Hunting Trophy Deer. 1977