I have a friend here at Baylor who sends out an e-mail each day with a portion of Sertillanges The Intellectual Life (thanks Lewis!). In today's section Sertillanges writes about the importance of using the time that one sets aside for study well. I think the following quote is particularly helpful, so I include it here.
We come at length, after speaking of the preparation, and the prolongation, and the profitable interruption of work, and of rest in view of work, to the work itself properly so-called, and the time devoted to studious concentration, to full effort. Accordingly, we shall give the name of full moments, moments of plenitude, to these culminating periods of the duration of our intellectual life.
The greater part of this treatise has no other object than to consider how to use that time: here we are speaking only of securing it, putting it on a stable basis, preserving it, guarding the "interior cell" against all that threatens to invade it.
Seeing that the moments of our life have very unequal values, and that for each of us the adjustment of these values obeys different laws, we cannot lay down any absolute rule; but we must insist on this one thing: you must study yourself, consider what your life is, what it enables you to do, what it furthers or excludes, what of itself it suggests for the hours of intense activity...
Whatever decision you have made, the chosen moments must be carefully secured, and you must take all personal precautions so as to use them to the fullest. You must see to it beforehand that nothing happens to crowd up, waste, shorten, or interfere with this precious time. You want it to be a time of plenitude; then shut remote preparation out of it; make all the necessary arrangements beforehand; know what you want to do and how you want to do it; gather your materials, your notes, your books; avoid having to interrupt your work for trifles. (p. 94-95).