I have travelled a bit, and so might be able to contribute at least something useful here, even if they may be common sense pieces of advice.
*Never carry all your money in one place. Put bits of it in your bra, socks, shoes, behind cards in your wallet, etc, for just in case. Also, don't rely on credit cards. Make sure you have some actual money on you or you will regret it if something goes wrong.
*Make sure you are aware of how you should be dressing in the country you are visiting. In most Asian countries (excluding bits of China, Hong Kong, Japan, Singapore) you will want to be wearing shirts with sleeves, not singlets (or they most definitely wont let you into temples) and for women, mostly covered legs at least to the knees. If you are travelling south-east asia then you will want to be wearing a skirt (to the knees at least) and trust me on this, you will get very very hot if you are wearing tight jeans or something for fashion. Dress practically and modestly when travelling.
*Try to be as minimalistic as possible; don't bring laptops (unless its for business) because it will only be a hindrance most of the time, and will also at times act as a flag saying 'I'M RICH! MUG ME!' depending on where you are travelling to. Most countries, even some of the poorest (Cambodia, I'm looking at you) will have internet cafes, for cheap as chips, where you can get your computer fix. But think, you can use the computer at home, but how certain are you that you will ever get to return to this unique country?
Pack lightly. You never know when you may have to carry all your gear with you some long distance that was originally unplanned.
*Try to learn at least these words, for non-English countries: yes, no, thank you, hello, goodbye, 1-5 and, how much? Trust me, they will go a loooong way at times, and the native people will always feel flattered that you aren't just another ignorant tourist, in that you actually bothered to try and learn some of their language.
*Make sure you think before buying things. I sure as hell regret splurging out on a 70 euro coat, without even trying it on, while I was in Paris. When I did finally wear it, it was the right size, but thin as anything and gave me absolutely no cover from the wind when I stupidly wore it the first time on a boat ride.
Remember that things are always going to be over-priced in touristy places (Paris, Tokyo, LA) and think that really, you could probably buy something quite similar back at home for a fraction of the price, if you really need it.
*Always be super cautious. Never accept a ride from anyone, regardless of how friendly they look, and don't talk to people in situations that seem suspicious (You never know when someone will be coming around from the back trying to take your wallet while the person in front of you distracts you)
*My number one piece of advice: Avoid like the plague, the tourist tracks. Avoid them. You will get ripped off, for sure. Carve your own path! Walk the side streets of Paris to find your own view of the Eiffel tower! Explore regions you know nothing about! Often that will be most rewarding for you. What's the fun in being at a place that millions of others have been, when you could blaze your own trail through the city/country and see things possibly only seen by locals.
Hoped you found something here useful, if you bothered reading any of it xD