Dear,first of all congratulations for making your mind to quit smoking.You have just choose the right path to healthy life.If you decide you can stop smoking suddenly,if number of times you smoke is not very high.Other wise taper it down with firm commitment,take help of your partner or relative who is close to you.When you quit smoking your body will oppose it and you can have withdrawal symptoms like mood swings,fatigability,disturbed sleep etc.But this are temporary and be in touch with your family doctor who will take care of this effectively.There are alternative methods like nicotine patch,chewing gums available,but most important thing is your commitment to the decision which you already have made so you will definitely get success.All the best and keep it up.