When you're preparing traveling on your own, it's important to pack your bags wisely. That includes distributing all your valuables. For example, don't keep your money, credit cards, and electronics all in one compartment of your suitcase. If you're traveling with a carry-on and a suitcase, have some money in both of them so that if one gets stolen or lost, you wouldn't be left completely penniless.
Wherever you go, always keep your belongings in sight, especially when you're using public transport or standing in line. It looks silly, but wearing your knapsack on your front is the best way to avoid getting pick-pocketed or having your bag slashed. If you need to put your luggage on the ground, put it right between your legs, or better yet keep it on your lap. Don't let taxi drivers load valuables in the trunk - keep your laptop bag on the seat with you. Also, keep your valuables locked in your suitcase if possible while you go out. Bear in mind that cleaning staff often have access to hotel safes, so they are not as secure as they claim to be.