rule number one: eat pastries.
the portuguese love pastries. every few steps in portugal lies a pastelaria or a confeitaria. they are huge fans of sugary, bready delights with powdered sugar or custard or powdered sugar and custard. you can get a pastry and an espresso for less than $2.
pastry 1: lisbon, cake partially covered in chocolate with apricot jam filling
pastry 2: sintra, queijada. this is what they are known for in sintra. it's almost like a tart, with a thin crust and sugary cheese filling.
pastry 3: lisbon, puffy brioche-like pastry covered in powdered sugar.
pastry 4: porto, similar to pastry 3 but with custard inside. EVERYONE sells these. they are in all of the shop windows. it came from a place called pastelaria basptista. i like to think it was a religious act to eat it.