Placing and soldering the parts is often the last step in construction. However, depending on the method of making the PCB these steps might apply:
A Solder flood can be used to beef up the traces for higher current needs, or just to limit the oxidation of the copper.
A layer of acrylic paint can be used to limit the oxidation of the PCB copper . Crystal Coat is the most common.
Riveting for dual sided board solves plated though hole issue.