1. Eating many small meals a day.
Legend has it that if you do this, your body will need to work more on the inside and in the end, metabolism increases. But there is a drawback. If you do this, you burden your digestive system, especially if the food you eat is unhealthy.
2. Taking walks
Yea, walking makes your body move. It will increase the metabolism of a sedentary person.
3. Drinking cold water
Nonsense. According to scientific researches, that maybe true. But cold water will upset the internal body temperature and your bodily functions would be impaired, resulting in sickness. When you are sick, your body metabolism will definitely be lowered.
4. Aerobic Exercise
It works to some extent. When your body is accustomed with it, your metabolism will not increase any further.
Now here is the part where I reveal what I found out: one of the best metabolism-increasing technique: Interval training. This is anaerobic exercise, when your body works harder than your heart can pump oxygen; so when you stop, you need to really catch deep breaths. Interval training requires you to do light activities for a certain period of time, followed by super heavy activity and this is repeated for several times in succession.
How is this done? You can use gym machines, treadmills, bla bla bla. But I find all that too restricting. One of the best ways for me is jumping rope! You will jump until your whole body is tired and you will really really feel your heart pump. A feeling like no other. After a few days of jumping rope, you will KNOW that your metabolism and stamina have increased.