But be vigilant. Always try to stay in hostels, because you will meet lots of other people there. Don’t be shy about making friends BUT be wary of locals who try to befriend you , especially older men. Do what you can to blend in, although sometimes that’s impossible. Never get in a car with a stranger, unless it is other young people you have met at the hostel. Walk with confidence, even if you are lost. Do not be out alone at night in Asia, or southern Europe, although northern Europe is absolutely fine.
Be sure to write down the address of where you are staying and have it with you at all times, and be sure to have enough cash for a cab with you at all times. Believe it or not, after traveling all over the place and having a drink or two, it’s easy to forget where you left your stuff! This is really crucial. Bring photo copies of all your documents: passport, credit cards, train and plane tickets, etc. Be sure to make use of lockers, and lock your luggage to the seat on the train. Because you are alone, you will have to make caution your routine. Also, carry the numbers and addresses of local embassies in your money belt. Pack very lightly. Make sure you have at least one credit card PLUS your atm card. The more options for payment, the better.
If you find yourself in a scary situation, do not worry about offending anyone, GET OUT. Run if you have to, use force if you have to. Always follow your gut.
With all that said, traveling alone is immensely empowering. I have loved my solo travels and have no regrets. You will meet tons of great people along the way. Stay flexible about your travel plans and have a great time!