Determinants of Demand
When income of a consumers decrease then his ability to purchase goods and services is affected. and when the income increases, we purchases more goods and services.
Taste and Preferences:
When the consumer prefer chocolate more than coffee then you can expect the demand of chocolate to rise.Our tastes/preferences changes overtime, it can be influenced by friends or family.That is when friends or family introduced a goods or services like ticket to a hockey games compared to steak;this would increase demand for hockey ticket and decrease demand for steak.
Expectation of future Prices
If future price are expected to rise like for instance consumer expected that tea is likely going to be increase in price in future, consumers will stock up in advance just in case .Present demand of tea would increase while future demand would decreases.
John Sayre and Alan Morris, Principles for Microeconomics, McGraw-Hill Ryerson, 6th edition pg 493

Subsitues/compliments price
# of buyers