I have very DARK thick brown hair and i got THICK blonde highlights Lke 3 MONTHS ago.....?

you buy the hair dye that you want and at a store like sallys they have caps that have holes in them and you pull the strands of hair that you want to highlight through the holes and the underneath hair is under the cap so it will stay the same color. its so much easier than foil! but you can always do the foil if you cant find the caps.