All the ingedients for making a cake should be at room temperature before you start. If the eggs are cold place them in a bowl of warm (not hot) water for a minute or two before you start.
Sift the flour 2 or 3 times from a good height on to a square of greaseproof paper. The flour can be easily added to the other ingredients by lifting the paper. Separate the eggs carefully. If any yolk does get into the whites, remove it with a piece of egg shell. Even the smallest amount of yolk in egg whites can prevent the whites expanding when whisked. The bowl in which you whisk egg whites must be scrupulously clean. To ensure this, add a squeeze of lemon or a dash of vinegar to the final rinsing water.