I'm pretty knowledgable on this subject. I work at gyms which sell products like these, and I'm skinny myself.
1) Eat something every 2-3 hours.Your metabolism needs a jumpstart.
I'm not saying avoid carbs. But do realize that carbs (if you eat some rice for example)...well ok if you eat rice, yes you're following the principle of eating every few hours, and it will help burn calories, buti t does slow the process of doing so. Don't carb deplete.
Cardio and weight training is about the best way to get calories burned. Running isn't for everyone, although for me, it's great. Burning a lot of calories, sweating a lot, and detoxing your system.
Avoid sugar. You're probably used to drinking sodas or something. Cut back on it. As much as possible.
I will say the drug that is proven to work (I don't even work for this company)...but I've seen the results at my job (I work at two gyms). OxyElite Pro. It's in a purple bottle. It suppresses your appetite, is a mood enhancer, and you will actually need to remind yourself to eat. It's dangerous though. Follow the instructions.
Some people naturally burn more calories. People with more muscle need to eat more, and you'll see them not gain weight much (unless they want to). For each pound of muscle on a person, an extra 50 calories are burned a day.
To sum this up, do cardio in the morning on an empty stomach. Eat at least one time every three hours. Perhaps an apple. Switch up the fruit. And don't always do fruit. Granola bar...yogurt. Whatever. Fruit have sugars in them as well. I'm not saying limit the fruits, but don't solely eat them as your snacks.
Doing the multiple meals way will prevent overeating. Normally when you eat 3 meals a day, breakfast, lunch, dinner, you're overeating. You're hungry at each meal and you're overeating what you should ideally be eating. Your metabolism is slow when you do that and it takes forever to burn that off. But before it's burned off, boom. Anther meal. You may have heard breakfast is the most important meal of the day. It's true. It wakes you up, energy, and starts your metabolism.
I personally eat a lot. A good chunk of my own paycheck goes towards buying myself food (not junk) just because my parents don't buy enough of the food I eat to last me. It's hard to tell you what to do without knowing how you currently eat, if you have any exercise incorporated into your program right now, etc. Basically your history. You shouldn't rely on us internet people to tell you what to do. Nutrition experts exist, and can take a good look at your health and give you the best option. What I basically said here is the generic version. It's what I do (minus the pills. I don't need them) and I am 5 foot 10 inches, and weigh 152. Eat my heart out. I eat partly because I'm bored, but also because I know I have to eat to maintain my metabolism.
Hope this helped. If you have questions, just shout.