I have spot n' stalked and silent hunted successfully many times. I agree the conditions must be right, most importantly quiet ground cover or strong winds to reduce the noise to your quarry. The key is chop off little bits at a time and slow/easy is the process. I watch the animal for its movements; head bobbing, tail motion, ear directional movements and attentiveness. If the deer is looking up or earing my direction I stop moving and hang tight. After they go back to their business I wait for few seconds and then slowly continue. Try and keep a visual but something between the animal to shield your movements and outline. Also control your breathing, if you feel like you heart is jumping out your throat stop and breath again
. Wind direction is a given for all types of hunting but paramount for stalking animals.