With jacket buttoned, there should be no tightness in fit. No bunching up of jacket, it should lay smooth on body with some room to move around in comfortably. If there is a vent in the back, it should fall straight down with no flaring. Pants should start at the belly button and you should be able to sit down in them with no tightness. There should be a slight to medium break at the shoes.
Cuffs are optional, but are strongly encouraged.
Again, a personal preference. Shirts can be many colors and shapes but the standard white should be somewhere in your wardrobe. Make sure the men's shop where you buy your shirt measures you correctly. European men prefer a more fitted, tighter look while American men prefer a looser fit. In addition to white, sky blue is another standard color that should be in your wardrobe.