Something that alot of people neglect is sleep. Sleep is important, right up there with diet and exercise. A terrible nights sleep can cause a domino effect that lasts all day. Too avoid this and have an awesome day, you can follow a few simple rules.
1.A Good day starts the night before. Make sure your sleeping environment is free for social distractions (cell phone, computer, TV etc). Try to make the room useful for one, well, two purposes. The darker the better. Don't eat a large meal right before bed either. Make sure you get approximately 7-9 hours of sleep, 8 being ideal. This may vary for some people, experiment to find your perfect time.
2. Wake up on time, do not hit the snooze button. That 15 minutes of extra sleep can throw your day off completely. That's 15 minutes you dont have to make a quality breakfast, thats 15 minutes you have to make up for in traffic. Thats 15 minutes you are late for work. See what I mean, the classic snowball effect.
3. When you wake up, start your day off with something invigorating. A warm or cold shower can really get the blood flowing. A nice little workout can release endorphins and get your heart rate up. Follow that up with a nice stretch and your good to go.
4. EAT BREAKFAST. I cannot stress this enough. Eating a good high quality breakfast can do alot of things for you. It keeps you from grabbing those pop-tarts at the gas station, it keeps you full until lunch and eat actually can help you lose weight. Studies suggest that when people skip breakfast, they tend to eat more calories in the day. Start out with some bacon, eggs, an avocado and half a grapefruit. What about cholesterol? Well life is too damn shirt to not eat bacon. So enjoy.
5. Appreciate the day. Go outside, take in a deep breath of fresh air. Sip your coffee, realize how amazing life is.
6. Don't start the day with news. Write down any ideas you have while your mind is fresh and fully recharged. Starting out with the news of some earthquake in some third world country is depressing, and that may carry with you all day.
And Finally, number 7. Attack the day. Don't just sit around and wait for things to happen. You have to set out with the goal to obtain something of value from each and every one of your days. Be a motivation for others.
Following these guidelines for the rest of your life will improve your outlook just about as much as diet and exercise.