In a healthy life there are 3 factors very important: diet, exercise and rest.
1- To have a good diary diet (but not at the weekend), you must consume fruit, vegetables, meat, fish and fresh products.
2- Lern to cook. If you don't know how to cook, probabily you will eat any thing like pre-cokeed food, we have to lern cooking technique like steamed, grilled, etc
3- Drink water and reduce soft drink consume. Water must be the main drink in a healthy life, we can consume soft drinks and juices, of course, but just at weekends.
4- Do exercise every day. The best is a sport that it likes you because it will motivate you, just 30 minutes all days.
5- Reduce the stress. It is one of the aspects more neglected that people don´t keep it in mind. It usually is for the job, studies or something stressful. Too much estress cause unhappiness and tiredness.
6- Get better sleep time. You have to sleep more than 8 hours and you have to use a good position, pillow and mattress. You musn't have electronics gadgets near you because they hinder your sleep.
7- Not smoking. Smoke will hurt your lungs.