my advice is the opposite : first upgrade wall then put three men from where the first attacks come then expand and upgrade 2nd tier infantry as fast as possible. traps and barricades never use them except mines which you detonate by clicking them in battle. cannons that fire alongside the wall (pickle guns) are really nice and some infantry to protect dead angles. beware of english snipers
 "Master of Fortresses"){kind=icon}
 "Protector IV"){kind=icon}