its easy sweetie...
1} you must wash your face with a face wash immediately when you get up in the morning or when you get from any sleep to remove the oil.
2} you must be aware that you must not over play in the sun or dust.
3} after the bath you can use ordinary sun cream in the summer or winter cream in the winter.
4} every month or two weeks apply nice face pack to remove the upcoming pimples
5} try to sleep well or otherwise too much work will result fast ageing skin.
6} don't try to wax every week, two or three. it must be done once in a month or two otherwise dark patches will overlap your skin.
7} eat healthy diet and add more fruit, juice, and water.
8}don't do too much makeup or apply more powder to the skin to protect it from dryness.
9} avoid swimming till you get perfect fairness.
i hope if you follow all this you will look like a princess and everyone will start noticing you than your sister. but be aware from BOYS...