Any technique can be learned by studying models that require exercise before they can be successfully applied in practice. Some applications of models can be almost simple repeats of learning. At other times you have to make certain adjustments to achieve practical application.  

MODEL: Double check horse 

The double threat is a very effective attack resource where otherwise need to find a play, which does not always appear especially if one of these threats is a double check of horse; therefore double double check your threats horse version constitute a tactical resource that must be mastered to perfection by the chess player.

There is a practice that can give man a great accomplishment and, moreover, an opportunity to raise your mental effectiveness, which, as we know, creates a positive jump in the individual quality of each human being: habituation to feel our mental tone and learn to regulate it. During exercise you should feel mentally seeks to structure a sequence of actions (algorithm) whose skeleton or bone it is a particular model that adapts or adjusts to find the real solution to a problem. Do it and do not forget that the goal here is total Chess, in principle, self improvement and our motto is Everything starts in the mind.