State the problem in plain language describing how each of the required output signals should behave in terms of the input signals.
State the number of inputs and outputs in your circuit and give each an appropriate name. It is best to choose a single letter for each name so that equations describing the behavior of the circuit will remain compact.
Determine the relationship between the inputs and outputs. That is, derrive a boolean equation for each of the outputs in which the output is the dependent variable and one or more of the inputs are the independent variables.
Draw a Karnaugh map for each dependent variable based on the independent variables that describe it, and use the map to simplify the relationship.
Draw the schematic for the completed circuit direct from the simplified relationships. The Karnaugh map will derrive the simplest expression for each output as a sum of products. Each product is captured by an AND gate with as many inputs as there are literals in the product. Each sum is captured by an OR gate with as many inputs as there are products to be summed.