The factors affecting the market demand include all those factors that influence the individual’s demand, i.e,
price of that good
prices of substitute and complementary goods
income of the consumer
tastes, preferences and choices of the consumers
other factors affecting individual's consumption decisions.
However, in addition to these factors, market demand is also affected by:
Number of buyers in the market: Larger the number, bigger will be market demand.
Income and purchasing power of the people: Merely large number of consumers is not enough; they must also possess sufficient income and adequate purchasing power.
Income distribution in the society: A more equal distribution of income means everyone has some money to spend and higher will be market demand.
Age and sex composition of population: A market with more females than males will have a different level and pattern of demand than the one with more males and less females. Similarly, a market with more young people will have different size and sale volume than the one which is predominated by the older people.