The best advice I can give because I am raising two of them. One eighteen, the other thirteen is lots of love and patience and understanding. they go through so many mood swings. I used to think that it would get easier as they got older but boy was I wrong. It only gets more complicated and other issues come to a head.
But on the other hand, our kids are very close and I enjoy them when they come home for lunch and when they come home from school and they can also be such a big help to me around the house.
Tell them you love them everyday. Despite how old my kids are, I still get a kiss and a hug from each of them everyday when they leave for school.
Oh, and reverse psychology works quite well too depending on the problem at hand.
Good Luck. I'm sure you'll do fine.