"Pace yourself. Plan rest periods into your day. Don't work so hard you are completely exhausted the next day and it takes you a week to recover." This is advice I give to my patients with congestive heart failure and COPD and other chronic illnesses on daily basis.
It is good advice for someone with chronic fatigue as well. Especially on the good days, when I am feeling energetic and ambitious. I have learned that if I work too hard or stay up too late on days I feel good, I will pay for it the next day--or more like it, for the next week. Planning a time to just lay back and read or to take a nap is essential for me in managing fatigue even on the best days. On work days or days when I have to be out and about all day, I try to plan a bit of time to sit and shut my eyes for a for moments and breathe deeply. I often take a short nap when I get home from work before doing anything else.
I will confess that somedays, like today, I feel like I am living life at a snail's pace. But with planning rest periods into each day and giving yourself permission to slow down on good days, things balance out, and in the long run there will be fewer really bad days.