what not to do? of course, do not destroy life (stop wars) or nature and do not support people / political parties / organizations (NATO) / corporations etc. which are involved in the destruction process ...
what to do? that's easy, but please DO SOMETHING good ... protect the nature, clean-up the nature whereever possible, eat less meat, consume less and try to buy sustainable products, support peace and freedom, join movements which are against wars + unfairness, like the OccupyWallStreet (OWS) movement, greenpeace, WWF, ... damn, there are so many movements for the good, just support / join the ones which fits to you :)
btw, when in or close to NY on sept 17th, you could join the OWS fellows at their 2nd anniversary demo in NYC (zuccotti park ~ former liberty square):
and always remember, there is no planet B.
if you have time, maybe you would like to read / watch more about 'safe the world' issues? well, i have few link libraries with interviews, videos, movies, pictures here: