How can I stop Smoking

I am 41. I started smoking when I was 22. Last year I had a mild stroke because of Ritalin abuse. I am suffering depression and I took around 20 Ritalin in one day to feel happy. But It made me a stroke on the next morning. I do not have any other addiction except cigarette. After the stroke, I stopped smoking for three months. After three months I started smoking ten (Mild=Gold) cigarettes a day again. My doctors strongly recommended me to stop smoking. I have stopped smoking again three days ago. I have made a strong decision to stop smoking because it is only my risk factor for stroke. My blood cholesterol and sugar are in normal range and MRI, ECG, Blood test and other medical examinations did not show any other risk factor. I go to walk at least 30 minutes a day. And if I stop smoking successfully I can return to my normal life again. I have made a strong decision to stop smoking. I do not want to put my health in danger because of a bad habit that I do not enjoy it. I am pretty sure I will be able to stop smoking because I want to live for many years and have a healthy life.