When I see a nice girl say at work or in a similar situation, I just cant make myself do the eye contact and smile thing.. its like in the smile and eye contact you are telling them everything, like I was at work today and I came back onto the shop floor coming off my break, looked up and there was this girl looking straight at me in my eyes, as soon as I knowtised I just looked away like a timid fag.. how the fuk do you overcome this shit?

Force yourself to make eye contact with strangers in the street. Not even good-looking ones, just look at random people and smile. Eventually you'll be able to work this on attractive members of the opposite sex, too, once you get used to it.