Love the story of the stalk across the fairway to get to a hare. I've had a very similar stalk down a slight incline in the middle of a farmers' field onto a hare. I was wearing gloves and an issued windproof smock with the hood up, ditched my bag at the top of the hill and crawled about forty yards to the hare. Near the end, every inch I crawled I expected the hare to get up and run which would have been a bummer as I had crawled so far and put in such effort on the stalk. I gave myself a target to reach, a clump of grass, and then I would take the shot. I reached it and put the hare down in one, a very successful stalk and it was a great feeling that I could move over completely open ground into a firing position without disturbing my prey. Fortunately for me, it was a warm summers day and the hare was pretty much snoozing in the sun, and I wasn't soaked through and shivering!
Lessons to be learnt on the stalk will become apparent over time and you will still make mistakes or miss opportunities. Some animals are a bit more wary and will bolt at the slightest movement or sound whilst others will sit long enough for you to pop one into them. Remember, things are seen for a reason, if you can eliminate them then you give yourself a better chance.
Shape - Man is a unique shape, if you can break that shape up by either crawling so that you look like a four legged animal or wearing a massive ghillie head set to break up the shape then you will give yourself a better chance. Personally, I just pop the hood up on my windpoof smock and crouch over!
Shine - Skin will reflect light, and it doesn't matter if you are black or white skinned. Cover it with camouflaged cloth or get some cam cream on! Don't forget to take it off before you leave your shoot if you opt for the cam cream, folk will think you are weird otherwise!
Shadow - Difficult if you're in open ground, but if there are large trees then skirt alongside them.
Silhouette - Don't skyline yourself, keep a good backdrop of trees and foliage if you can. If you are readying yourself to take a shot and have stalked into position, then don't climb on top of the mound to shoot but come round the side. Only your head and shoulders will be visible and you won't be right up against the sky casting your silhouette.
Sound - Creep about like a ninja and stow your rattling kit properly. I used to take a water bottle shooting to keep hydrated but the glugging noise of a half filled water bottle seemed really loud to me so I canned it. I could wear a camelbak instead.
Smell - Your scent is made up of man made chemical soaps, fried breakfasts and beer! You want to smell of mud and twigs! Animals will find your smell alien and will take notice of it. Use the wind to your advantage and stop washing. Roll in mud and twigs and explain to the missus that it really is necessary. Expect to be sleeping on the couch for some time!
Spacings - Only a problem if you are shooting with a whole bunch of other people, I doubt animals would pick up on it but it is what a human would pick out straight away. Straight lines, such as a gun barrel, could give yo away. That is the reason snipers cam their rifles up. You can break up the shape of your rifle by simply wrapping it in one of the old issue face veils. Remove it after shooting, especially if it was raining, you don't want your rifle to rust.
Movement - This, IMO, is the one thing that will give you away. I have crept up on young rabbits to within a few metres DURING THE DAY before I was noticed. I was wearing the trusty windproof, no special cam gear. I once caught a young rabbit in my Tilley hat and put it in my pocket, Ratbag made me put it back though! That was at night, but if you move slowly, you will do better. You can move faster when in the shadow of trees, crouched over, or by using other terrain features to your advantage. Sound may then give you away though.
All in all, it is a combination of things that will give the game away: the stick under the leaves that you didn't see and snapped, getting caught on the barbed wire and it pings as your jacket rips free, loose pellets in a tin shaking, etc. If you can eliminate all of these, then you give yourself a greater chance.
So basically, a good DPM jacket (washed in soap flakes is a bad idea as they contain UV brighteners which animals may see. Just rinse it through and hang it on the washing line for a few weeks. The sun will break down UV brighteners, the rain will wash it out too, and the wind will rid it of unnatural smells.) with some basic gloves to cover the hands and a face veil and hat, good trousers and a pair of boots will see you right. Remember, even polish on your boots will give off a scent, so be careful what you do before you go out.
Some look a lot better close up than they do at distance, but having the choice of patterns and colour schemes such that you can better match your local area has to be better than having to accept whatever the army has too much of! Also, you aren't just hiding from little fury mammals with poor colour vision. You also want to be invisible to birds. Some may be targets for your gun or camera, many more will simply sound a piercing alarm if they detect your presence. There are few things as annoying as being scolded by an unseen wren when you are trying to be invisible! 
