Drink protein milk-shakes
As long as you eat, 3 times a day being slim is good =p
Eat lots of junk food!
Work out strenghwise to gain muscle which weighs more than fat
Be happy. Some people would do anything to be like you. Im quite slim and sometimes i wished i weighed a bit more but then i think that people always want what they cant get=)
Allot of calories, if your a vegetarian then ignore this. You need allot of fats and proteins that come from meat, eat steak, pork, chicken and some plants that have allot of calories are peanuts and spinach. But as long as your healthy you shouldn't worry about your wight.
Macdonalds breakfast kfc for lunch maccies for dinner burger king for supper and non stop fries and coke for snacks!