How can I improve my evaluation of exchange positions? I am a casual chess player and I have recently identified a weakness in my play when it comes to positions where there is some "tension" on the board. By tension I mean that a series of capture and recapture can arise from the given position.

I have gone through a fair bit of tactical training and it made my mid-game play decent enough to sometimes gain a significant advantage but too often, I tend to lose this advantage when exchanging material. 

See the example below where (please refrain from laughing) I played an impulsive Nxd5...

[FEN "r4rk1/ppqb1p1p/5Pp1/1Bpp4/1n1P4/2N1P3/PP4QP/R1B1K2R w KQ - 0 15"]


I feel like I am missing some method to analyse this kind of "tensed" position and that it leaves to much space for my irrational-self to make decisions! 

Is there any method/book/training that would teach me how to approach positions where a lot of captures/recaptures can occur?
A very good and old book is Think Like a Grandmaster by the Grandmaster Alexander Kotov. He was first to put forth the idea of candidate moves. Kotov recommended looking for several moves that seemed feasible – the so-called candidate moves – and then analyzing those moves one at a time.

Once you have found a good number of candidate moves, you may then begin to systematically analyze these moves. The idea behind candidate moves is to help structure one's analysis and prevent it from becoming jumbled.

Finding the correct candidate moves is obviously one of the most difficult aspects of becoming a better chess player. You may start first by screening all possible checks and exchanges (including Nxd5). Then, you will gain experience and will recognize important patterns. 

One of such "patterns" is the safety of the enemy king. In the given position, with the pawn in f6, the king in g8 is very unsafe and a nice pattern would be to mat the black King wth Qg7! So, I would have selected 1.Qg5 as my first candidate move!

The only answer is then 1.Qg5 Kh8, to counter 2.Qh6 with 2...Rg8. However, in this position, I recognize a new pattern Qxh7 and mate in the h-file with a rook in h4 for instance. So, I analyse 1.Qg5 Kh8 2.0-0!! to bring the rook h1 into action and nothing serious can prevent the plan Rf4, Qh6, Qxh7 and Rh4.



Another very good book is The Critical Moment by the Grandmaster Iossif Dorfman. Chapter 2 is about The exchange of material answering a crucial question: For which exchange should I aim?