Sayings and idioms are very important to raise your level in any language. If you're interested in learning some Portuguese expressions, here's a link to a site where you can find plenty of them: Provérbios Portugueses.
P.S.: all sayings are in Portuguese only, so you'll need to have an intermediate-advanced level to understand them. Anyways, remember that you can always create a new sentence discussion if you have any questions.
In addition, Wikipedia also has a List of Proverbs from all Portuguese speaking countries with their equivalents in English. Don't forget to take a look