For the last few months, I've been extremely busy. I've got a full teaching schedule, I'm a graduate student in mathematics, I run my own business, and I do freelance writing. My day usually starts at 7AM and ends at 11PM. Being able to schedule my day is really important and I use a variety of high-tech and low-tech solutions to get me through the week. For a few months, I didn't check my email in the mornings. One of the reasons why was that I had to immediately start replying to emails and get tasks done. This took time and would derail my morning routine. Instead, I sat on the sofa, drank my tea and took time to wake up. I've been using Inbox Zero for most of this year and I've recently actually managed to check my emails in the mornings without hampering my schedule. I don't do it every morning, but from time to time, I manage to check my email in a few minutes.
Any task that I need to accomplish, I'll usually write it down somewhere. I've got a stack of papers from my daily Moleskine calendar that I use for this. Making lists is a really good way to do so. You can also send yourself emails. Since I use Inbox Zero with Gmail, these tasks will get done very quickly. Google Calendar is also a great tool. If your schedule is pretty loaded, then using Google Calendar will makes things clearer for you.I also use a daily planner to jot down stuff as well as a paper-based calendar, in which I like to cross out the days. Why do I use paper alternatives instead of just using electronic versions? It's because that every time that I open up Gmail, I end up doing more work. So when I don't have time for this, I can easily reference a paper calendar or a daily planner to see what's up. It's also easier to carry and modify on the fly.
When you are busy, you need naps in order to get through the day. I like to take daily naps, which vary from 20 minutes to an hour, depending on how much time I have. This usually happens during my lunch break. It's a perfect way to recharge your batteries. After a nap, I like drinking a cup of coffee to fully wake me up.
If you are very busy, the trick is to find some time to relax, no matter what. For example, I tend to sleep in late on the weekends and I usually don't do much on Saturdays. It's the day that I recuperate from the week, taking a long afternoon nap and taking it easy. It gets me ready for the week to come.