Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
If you are doing a Clear Glitter Flake:You need to sprinkle it on top of a wet plastisol then cure it.Its called Sugar glitter.The clear flake is able to reflect the light is because it is sticking out of the ink. The only other way I know of, to create this effect with direct printing, is to use a base that evaporates/shrinks back from the flake. I am not aware of how to do this as a transfer.....Best of luck!