Smoking makes your body very unhealthy and weak. It makes it hard to breathe. Well, if you try it once, maybe you'll try it again, and keep doing it and before you know it, you're addicted. Cigarettes have something in then called nicotine which is very addictive. Even if you want to stop, it would be very difficult.
Cigarettes can also get very expensive.
If you get hooked and smoke packs a day, that's a lot of money a week. Smoking can also stain your teeth yellow and make them look ugly. They can also stain your fingers yellow and brown from holding them. Also you and the people around you when you smoke will smell badly. So, as you can see, smoking has no good points.