Summerholiday in Portugal, looking for do's/dont's Anything and everything

Hello people! I'm thinking about going to Portugal this summer. I've never been in Portugal, any Portuguese people here with info?:D

Good destination dear! :D i had the same idea for this summer

But where to go? What area's to avoid or definitely must- sees? :D

How long you plan on staying there?
I wanted to go to the Azores, but i found that get there it's very difficult. Best destinations are: Lisbon obviusly, charming Sintra, Coimbra, and Oporto (where was born my favourite wine "Porto")

I'll look those place up! Thanks!