Eat where the locals eat. Street food is delicious and in many countries, vendors are the place to hit up if you’re hungry. If it is a popular stand, it will more than likely be okay.
Have drinks in the local watering hole, but do not get incoherent or black-out drunk. You are still in a different country and some people won’t think twice about stealing from a foreigner…or worse.
Always lock up your belongings. It’s only the one time you don’t lock that your stuff will get stolen.
Keep a copy of your passport in your e-mail or with your travelling companion.
Bring comfortable shoes.
Keep in touch with people back home. If something happens to you, then someone knows where you are and who you were with. Social media makes this very easy.
Call your bank and credit card company and let them know where you will be. Otherwise, you may find your card has been cancelled. It is also a good idea to have a back-up debit or credit card that is kept separate from your other one. Just in case.
Ask locals for their advice on everything from where to eat to what taxis you should/should not take.
Have a general idea or exact address of where you are going when you first arrive in a new country. About 90% of the time, Border Control will ask you where you are staying and for how long.
Get your nose out of your guide-book and have fun! Travel is all about the experience.