Both the British force at Baltimore and New Orleans took heavy casualties at the hands of American militias in entrenched postitions. And despite holding Pensacola and capturing New Orleans, the British lost the campaign.
A better strategy for the British would be to raid the strategic port towns in Georgia, the Carolinas, and Virginia, where the American militias are not so numerous. These raids would have the advantage of allowing the British to destroy goods and stores along a coastal path of destruction that could be conducted by land or sea.
This strategy would deny the Americans victory points gained by attriting the British forces, and allow the British to gain easy but valuable victory points by simply destroying or capturing goods and stores.