(b) Cigarette smoke contains nicotine. Nicotine is a vasoconstrictor that reduces the diameter of some blood vessels. (i) Using this information, explain why smoking increases the risk of developing cardiovascular disease (CVD). How do I approach this?

Good question. You must think about these questions in progressive steps. The first step is given - vasoconstriction. What does this cause? A reduction in the diameter of the blood vessel. So you've got the same volume of fluid running through a smaller space. So we can comfortably conclude an increase in pressure. What does this cause? What's the next step in the chain of effect? This pressure causes a strain on the artery walls, resulting in damage to the innermost walls of the artery - the endothelium. What happens next? There is damage ("cracks and cuts") on the innermost wall, these "cracks and cuts" are spaces that cholesterol and other plaque forming substances (calcium etc.) can deposit in. What is a fatty deposit called? Atheroma. This will slowly grow and cause atherosclerosis. One extra step, touches on the idea of feedback loops. What happens when there is damage in a blood vessel? Platelet are activated and then aggregate. Platelets will begin to form a clot until the wound is clotted. This is an example of Positive Feedback.
"The Key" with these kind of questions is the chain of events and effects. In the human body that is how everything happens. A cascade of events caused by an initial step. The next step is very intuitive and all it requires is a bit of methodical thinking, and you've hit 4 marks on the mark scheme for a 3 mark question.