There are four key points to remember to start a PCB designing:
SCHEMATIC STUDY: Schematic study took a major role in PCB designing . One should always know to study the schematic diagram and to create the proper schematic diagram. Before moving into the board design one should check all the errors that might be possible while creating the Schematic Diagram.
SIZE OF THE PCB: Size of the PCB is the second most important part to start the PCB designing. One should always know the required size of the board before getting started into it.
TYPE OF THE PCB: One should always know the requirement of the clients whether they need single layer or double layer PCB. One Should always know whether the client needs through hole components or surface mount components.
FIX PLACEMENT OF THE COMPONENTS: Before getting in to the board section, one should always confirm whether the components used from the library are as per the requirements. This should be done on the schematic part.