painting - applying a glaze?

[MILLWALL]

i've done the first couple of layers on my portrait, now i need to add some glazes, but i'm not exactly sure how
i've been told to dilute the oils using turpentine (someone evan said water?) but i have no idea how much turps to use, i don't wan't to risk erasing what i've already done, but i need the glaze to be as transparent as posible
does anyone have any advice?
thanks in advance

[xharlequinxlovex]

Use up as much turps as in proportion to how glossy you want, eg - 1 cup to 3 cups, I guess.

[Jwebbie81]

I don't know why you would want to dilute the oils at all. That would just make them runny....