Basically, the order in which you mix the products does not matter. I usually add salt, sugar and vanilla to the eggs and mix everything well. Then immediately pour in all the flour and whisk well until smooth, so that there are no unmixed lumps of flour. Then milk.
Many more advise letting the dough stand for 15-20 minutes so that the gluten will disperse and supposedly the pancakes will turn out to be more elastic. But I will say from my observations, I don’t see much difference between the first and the last pancake, so whatever you want. I don’t do that.