Use room temperature egg whites as binding agent and add a little condensed milk.
Whip egg whites until soft peaks form to get a fluffy and light texture.
Make sure to not overmix the batter to avoid deflation.
Make sure the macaroons dough is moist to get a crispy texture.
Shape macaroons evenly and use a stencil or a silicone baking mat with macaron templates for accurate sizes.