For newer pilots and even for some of the more experienced ones, judging "E" states remains one of the hardest things to get right. The simple fact is there is no formula or process for doing this AND being right all the time, it's something you have to evaluate as it happens by analysing the clues available when observing the enemy as he approaches and conducts his aspects of the fight. It requires you to continually adjust your approach and how you conduct your aspects of the fight to counter your opponent, be it defense or offense.