Anyone can improve their pressing by good coaching and game time. In fact anyone can improve any aspect of their game by good coaching. When Benitez was first at Liverpool he religiously coached and drilled Pepe Reina on his positioning, where he should be depending on where the ball was and where the strikers were. I had a mate of mine who worked at Anfield at the time and he used to go over exactly how detailed this stuff was, it was eye opening. Result he turned Reina into one of the best goal keepers in Europe. It's the same basic principle, drill people until they can do it without thinking. It's not difficult but it does take a lot of hard work and attention to detail by the manager and coaching staff.