Car is an emotional product and buying one involves a lot of decisions being made. While there can be many factors which can influence the decision to buy a car, the first thing which needs to be considered is the end use which effectively means the average distance it would cover a day. If its more than 50 kms, its better to go for diesel, else petrol. Price is always a big factor as it has a direct relationship on the obligation being added to monthly expenses.
Next in the line is the number of service centres followed by the size of the car. The first factor decides the brand, the second one decides the price