English sayings and proverbs

In my opinion, learning proverbs (proverb przysłowie)or sayings by heart could be a useful additional tool to improve your English skills.

Let me give you few examples:

Two wrongs don't make a right.

If someone has done something bad to you, trying to get revenge will only make things worse. 
Zemsta nic nie daje.

The pen is mightier than a sword.

Trying to convince people with ideas and words is more effective than trying to force people to do what you want.
Pióro jest silniejsze od miecza.

When in Rome, do as the Romans.

Act the way that the people around you are acting. This phrase might come in handy when you're traveling abroad notice that people do things differently than you're used to.
Kiedy wejdziesz między wrony, musisz krakać jak i one. (dosłownie: jeśli jesteś w Rzymie, postępuj jak Rzymianie.)

Zaczerpnąłem z następującej strony:
http://www.phrasemix.com/collections/the-50-most-important-english-proverbs

Time for a song.