The way to become skinny is to sustain a caloric deficit over time until you reach your desired weight.
Your body requires a certain amount of calories to maintain it's current
weight (body weight in lbs x 15)...so if you were 150 pounds, that would be
150x15 = 2,250 calories/day.
To lose 1 pound you need to be in a deficit of 3,500 calories. So if
you ate 500 calories less than this 2,250 each day (1,750 cals/day) you would
lose 1 pound each week.
Couple that with 1 hour of cardio each day (500 calories burned/h on
average)..you'll burn another 1 pound a week.
If you are really overweight or even obese, it will be easier to create a larger deficit safely and lose even more weight each week.
But bottom line here, do the above, and don't let your calories dip below 1,200/day and be patient....you will get there.
If you encounter any hurdles/plateaus..increase your cardio intensity/duration, decrease your caloric intake, or try cutting out carbs for 1-2 days (eating only lean meat/veggies).