First of all, enough and appropriate sleeping. Enough sleeping means - with at least 7-8 hours per day. Appropriate sleeping means - sleep at night around 11 to 12 pm as human have biological clock and we needs good sleeping environment.
Second, eat nutrition food - enough vegetable and fruit, less eating junk food. We will then be more healthy and so looking nice and smart.
Third, doing a little bit exercise in the morning and take a shower before going out. You will feel so refresh for the whole day.
Do somethings that you are enjoy. e.g. having high tea in the afternoon; walking along the beach ... OR doing somethings earnestly (認真) so that you will be so concentrate on something that you will not be feeling tired. People always said that -- someone looks so smart when doing things earnestly. I agreed.
A cup of morning coffee or tea is so refresh. (But don;t drink too much in the whole day)