Right Hun,
First roll the bottle in the palm of your hand, this will get the white to the right consistency...........
Load the brush with a little more paint then you would use for a normal white polish.............
Then apply in one stoke.......from side to side.................no down ward strokes to fill in the shadows..................... let it dry for 2 minutes and repeat if neccessary.......going over the shadow areas.....you will get lumps and bumps if you apply the second coat before the first is dry............. it moves the white, hence lumps and bumps.....tidy up the smile line if need be, with some nailfresh and a brush..............
Also never test if the white is dry with your fingers, because if it's not it will smudge and pull away from the nail........the smile area becomes flatter as the product drys.............If you make a mistake.......a little nailfresh on a lint free pad and wipe it off and start again..................
You will soon master this , with a little practice.............
hope this helps