Beauty is in the eye of the beholder. And what will make you beautiful is your character. For beauty is fleeting, but the character you impressed on other people is lasting.
An if we're talking about care of our body:
1) Sleep at 6-8 hours. Drink 6-8 glasses of water daily. Stay clean and take care of your skin. The key to good grooming is cleanliness.
2) Plan and organize your schedule. In this way, you may avoid cramming which can cause stress and lack of rest/sleep.
3) Be with beautiful people - people whose character and influences will positively have a good effect in you.
4) Finally, be yourself. If you are not Ariana Grande or Marian Rivera, then don't try to be one. There is also uniqueness in being beautiful. Don't be beautiful to impress other people, be beautiful to give glory to your Creator.