As for differentiating dilute, graywing, and clearwing, look at the face, wings, and body color.
Dilute - Pale blue cheek markings, extremely faint grayish face spots, pale silver-colored stripes, pale silver primary flight and tail feathers, highlighter yellow or pale blue body color. Usually not a ton of variety in darkness unlike with graywing and clearwing.
Graywing - Denim blue cheek markings, gray face spots, gray stripes, grayish flight feathers, blue-gray tail feathers, and a slightly lighter body color than a normal budgie. The shade of the pictured bird is the most commonly seen, though lighter ones do exist here and there.
Clearwing - Very slightly diluted body color and blue cheek markings, usually look undiluted at first glance (though sometimes the blue cheek markings are a similar shade to a graywing's). Black face spots are usually absent or extremely diluted. The stripes, flight feathers, and tail feathers of well-bred clearwings are usually quite faint, but there is some overlap between the palest graywings and darkest clearwings. Body and cheek color is usually one of the best ways to identify them.

(+cobalt violet)
Crossing clearwing and graywing results in a full-body graywing, or FBGW for short. These can be hard to identify, but usually have a graywing-colored tail with stripes that are lighter than a normal graywing. Body color and cheek markings are usually intermediate between the two.
Knowing this, can you guess which bird is which in this image? One is graywing, one is clearwing, and one is dilute.
