I'm a morning person. All other things equal, I do my best work in the first three hours after I wake up. If I try to get the same work done later in the day it either takes twice as long or simply isn't possible.
Yet somehow I can always attend a meeting or respond to an email. So I try to cluster these activities together, and tackle them later in the day when it's harder for me to do individual work.
Not everyone is a morning person. I have friends who work their magic in the afternoon, or after everyone else has gone to sleep. It's worth figuring out when you're at your best. Once you know, use it to do your best work.