Some days it is really hard to sit or lie there for 10 or 15 minutes. I think the valuable part is in just watching what your mind does. Some days it will be cooperative and calm down but other days it is all over the place. I agree with SoupDragon that it is a practice and that is what it requires - just keeping at it day after day. It can also be very helpful to find a sitting group/sangha to meditate with from time to time. They usually meet weekly and having the contact with others who do the same thing has been helpful for me.