There is a detailed description of checks to be performed prior to manufacture of your printed circuit boards in the FAQ What checks should I perform before having PCB produced?
While designing your schematic and PCB layout, it is to ensure that they are same. During design all the checks in the above document link can be used but there is one check that can be regularly and quickly performed to ensure pads connect to the correct net Schematic/PCB Check..
Important Note: This does not check net connectivity which should be performed using the Reports options
From the menu bar launch Tools-->Schematic/PCB Check..
The checker compares copies of the netlist for the schematic and PCB designs.
The result is a report which lists any discrepancies found. This should enable these faults to be found and corrected. The follow example shows an additional wrongly routed track.
Once you have corrected all errors, repeating the check you will receive a message stating "The designs are the same" i.e. the pads are connected to the correct net.
Design changes should always be made to the Schematic and brought forward using the Forward Design Changes option.
The built in help document provides additional information.
How can I check the PCB Layout?