Couple of tips which takes practice, but can make a huge difference:

1. Always know your escape routes (primary and secondary are fine), this includes at restaurants, hotels, shopping areas, etc. Any enclosed places. Look for them when you enter and burn them into your mind.
2. Have your serious don't-mess-with-me game-face practiced. Works wonders when people you don't want, approach you. A smile might be natural, but game-face tells them you are not an easy victim. Stand tall, turn your shoulder towards them, put your hand out in the 'halt' position, and look them in the eyes and state 'no' in local language
3. Know a few basic words in local language. Yes, no, police, please, thank-you, help is a good start
4. Know where the closest place you can get help: US embassy, hospital, police station, airport, etc. No use in running, if you don't have a safe-haven to run to. Even places like a bank can provide shelter and give you time to request for assistance.
5. Have a guardian-angel. Someone whom you communicate with to tell them where you are, where you are going, and when you will check in again. If something goes wrong, you WANT people to raise an alarm and look for you. Have your phone configured to send a geo-tagged alert to this person if you get into trouble. Use it as a panic button. Several apps out there for this.
6. Have the US embassy on speed dial. Also have a local map downloaded on your phone (for use even without service)
7. Practice situation awareness, for single and multiple threats. This takes practice. Watch those who are watching you. Then see who they look/talk to. Add them to your list. Move away and see if they follow. Use reflections/mirrors, peripheral vision, obstacles, perches, and over-the-shoulder talking viewpoints to your advantage.
8. Blend in. Look at local attire. Buying a scarf, shirt, or hat is a cheap way to blend in, especially with your golden locks.
9. Learn practical defensive moves to quickly disable and disorient an attacker with a single strike, so you can quickly egress. Also learn disarming techniques from hair-grabs, chokes, and blades. Remember the goal is to egress to a safe location.
10. Don't be overconfident and listen to your inner-voice when it is telling you "something is not right". Your subconscious picks up a lot more than your conscious. Listen to it.

Hope this helps. I have traveled to a few hot-spots as well in my time. Be smart and safe. Happy travels.