When you are practicing and just as the moment occurs eg:when you slide over that double in a ghost count, does anybody else experience a sort of blinking of the eyes and a sort of "blanking" of reality for that split second the dirty work occurs.
Its hard to explain, It used to happen a lot when I started out, I didn't even realise I was doing it at first. can anybody explain this?

Yes, you are convincing yourself that you don't see the move when it occurs, so other people won't see it either!!!!!!

Just last night I was having a conversation with one of my Mentor's (Thank you Brian) about the body language that many of us exhibit when learning a new Sleight. At the moment when we do something such as a false take the newbie tends to either raise their shoulders a little or their eyes look in the wrong place. This telegraphs to the onlooker that something might be amiss and never looks natural. In essence we need to convince ourselves that real magic has happened NOT that we are deceiving the audience by doing something in secret.
Basically, unless you are a professional liar or a psychopath you must learn to deceive by being very natural and once you get to the level that you yourself can believe in the Magic you are producing, your audience will also believe in that Magic.
In the case of a false take, one must first take the item for real and do this hundreds or even thousands of times and carefully take notice of how it feels and what it looks like, only then are you really able to now practice the false take and make it feel and look like the real thing. Every little detail must be taken into account. It is the little things that can ruin an effect such as a blinking of the eyes or looking in the wrong place and even an unnatural pause or pace of your speech.
A problem that I had with the French Drop was leaving my "empty" hand right where it was when I "took" the coin. When I really took the coin I noticed that my now empty hand dropped to my side. This is what I need to work on, being natural and making my actions and my body language look the same whether I really take the coin or only pretended to take the coin.
I hope my ramblings have been of some help.
Iven