If you don’t have an egg separator, the usual way of separating eggs when you need only egg-whites or yolks is to crack the egg neatly in half and tip the yolk back and forth between each half shell retaining the white that remains after each tip. I inadvertantly discovered another method while separating the eggs needed for making Honey Nut Nougat.
Using a butter knife, make a single crack in the side of the egg, about 1.5cm in length and just deep enough to break the inner membrane without breaking the yolk. (If there are any little bits of shell around the crack, carefully remove them/ wipe them away.)
If the crack is about 2mm wide, most of the white should drain out in this way. Use the knife or your fingers to “break” the stream off at the egg if it doesn’t break off automatically; egg-white is quite thick and gloopy. Just keep a close eye on the crack to make sure no yolk sneaks out too. When as much white as seems to be possible has drained out, carefully crack the egg the rest of the way and do the back and forth thing just for any last little bits. If there really is just a tiny amount left around the yolk, leave it, and do the next egg as needed.
(Another little tip: I always separate eggs over a dedicated small bowl and not over the mixing bowl, in case some yolk gets into the whites and I have to start over. Even a little yolk in the egg-whites means they will not stiffen when beaten. Similarly, any water or oil in the bowl will prevent stiffening of the egg-whites. Always make sure the mixing bowl is clean and dry. Wipe with a paper towel to be sure.)