Working on heavy pieces games

As indicated before and verified by my error db, I started working on my play with heavy pieces (queen + rooks). I bought and work with:

I only started - but the positions and explanations so far are pretty insightful and yet so familiar to the mistakes I make...
Here´s a typical position  - White to move:

How would you continue? Rxh7? So did I - and it loses!  But how - can you see the refutation?!

(What somewhat scares me: I am sure that Black wouldn´t see the refutation neither. But since Black can´t do anything else anyway, he simply can wait until it becomes his "last resort"; whereas White better calculates it to the very end...) 
So for now, these examples are rather scary and not yet increasing my self-confidence; but I am convinced it will chance soon!  This book will surely elevate my understanding on how to thoroughly act with heavy forces!