What can the public and US citizens do to make us more secure?

Other than taking off our shoes at the airport. I’m sure there are laws that could be, should be passed but something along the lines of Bill Mahers picture book if you know what I mean. Without putting up anti-car barriers or police our public grounds more or gathering intelligence. I know that the citizens of the last world war used to have scrap metal drives and such. Should we not allow cars to park idle in front of buildings or can we carpool?