Understand and define the term "monomial." Mono means "one." So you will be looking for a single algebraic expression.
Figure out the different types of monomials and what they mean. One type of monomial is a "constant," which is any single number like 6, 35 or 151. Another type is a "variable," which in algebra can be defined as letters like "x," "y" or "z." The third type of monomial is defined as a "solution" or "product" of a number and any number of variables, like 4x or 7ab.
Determine examples that are monomials. These include: (2xy)^3, 3ab and 2x.
Come up with what a monomial can't be. If you see an addition (+) or subtraction (-) sign within the algebraic expression, it is automatically not a monomial. This includes subtraction signs that are added to define negative exponents. For example: x - 7, 5x + 3 and 3 + 4x - 2b.