I believe you can get better at playing defense through the "defensive fundamentals" improvement. Using the right technique, practicing your defensive skills and learning how to read the offense…
Very often we, coaches, "forget" about this, and use the players lack of desire to justify a bad performance (sometimes it happens, but not as often as we hear or read) It's not 90% will and 10% skills, that's poetic, but not true. In any case, if we want to talk about percentages, let's go with 100% will and 100% practice, in order to play the best defense you can.
This week I saw some nice examples of good defensive efforts, understanding them as will + practice. Here are three of those: two big guys, Ratko Varda from Mega Vizura and Serhiy Lishchuk from Valencia Basket, and one small, Sergi Llull from Real Madrid.
Varda stops a penetration and then, with quick footwork and realizing about his position on the court, slides and gets the position right outside of the semi - circle to force an offensive foul.
Lishchuk jumps to stop the ball defending a pick and roll situation and sprints to recover his man (blocking his shot, with very good timing)
Llull sees how his teammate loses his man and rotates to stop the penetration and the one on one. Slide, sprint, balance.
Let's take a look at the video: