The 9 "NEVER" you should take note while travelling to be safe.
#1 Never put cash in your Passport covers, the authorities may take it as bribery.
#2 Never put any valuables in your "check-in" luggage, it's not too hard to open it without you noticing. you can watch this video if you don't believe "Open Luggage with a Pen"
#3 Never wear shades in the airport, the police are constantly looking out for terrorist. You may be the first they suspect.
#4 Never help strangers to carry their bags, in 2010-2013 there are 9 thousand cases of drug trafficking using this method.
#5 Never leave your passport unattended, also beware of pick pocket who will swap your passport with a fake one. It's too late to realise when you are at the counter.
#6 Never talk to strangers unnecessarily, "social engineering" is commonly use to cheat you into doing something illegal.
#7 Never Drink any beverage offered by strangers, the next thing you realised you landed naked in some motel. They drugged your drinks.
#8 Never Take out all your cash when footing the bill. People will target you when you are alone.
#9 Never Sling your bag behind your back. The knife they buy is very sharp, you will not notice that they cut a hole on your sling bag and took away all your valuables.