Crowdsource your research.
Make a local friend.
There are lots of great networks to connect female travelers all around the world. You can ask them about the customs and things to do in their area, or even make plans to meet up.
Give someone back home your itinerary.
At least one person who's not traveling with you should have a general idea of where you'll be and when, in case something goes wrong or they need to get in touch with you.
Take pictures of all your documents and put them on a locked site like DropBox that you can access from any computer.
Passport, IDs, ticket numbers, reservations, etc. That way if you lose them AND your computer or phone, you won't be totally screwed.
International phone plans are worth it for emergencies.
If you don't want to spring for a whole plan, at least pack a couple of international phone cards with you in case you need them.
Consider travel insurance.
Places like World Nomads provide travel insurance to individuals, couples, or families to cover all manner of unexpected costs. For a reasonable fee they will not only cover medical and dental emergencies, but also reimburse you for lost baggage, trip cancellations, or delays, rental car damage, and more.
Schedule a regular check-in with someone back home.
Whether it's via Skype or WhatsApp or email. It's a good safety precaution, and then you'll also have an excuse to gush about your adventures as they happen.
Packing light can actually be a safety tip: Nothing says "rob me" like someone wheeling four large bags along the side of a street. You'll also be more mobile with a smaller bag in case you need to move quickly.
Have hard copies of your itinerary and important phone numbers with you at all times.
This can include the number and location of your hotels, rental companies, anyone you're meeting, an emergency contact, and the closest U.S. Embassy.
Don’t keep all your money in one place.
Keep some cash and a card on your person and some in your bag and some back at your hotel.
Genius tip: Store your extra cash in the bottom of a tampon or pad box. No one’s going to look in there!
Bring an external phone charger.
In some places, it helps to wear a fake wedding ring.
Call ahead to see if your hostel or hotel has a locker or safe.
If it doesn't, bring a bike-style lock and attach your things to something in your room.
Consider a slash-proof bag.
Especially if you're going to stay in hostels or other group accommodations or you're bringing expensive electronics like a computer or a camera, a slash-proof bag will help you feel more comfortable leaving your belongings while you go out and explore. It's like a portable safe for all your stuff.
Bring a portable door or window alarm.
These are cheap, easy ways to make any accommodations feel safer. The door alarm is also a jamb that can make shared bathrooms more private while you shower.
Pack a thin one-piece bathing suit.
If you're going to be in a protest or mob situation that can get grabby, wearing this under your clothes is a simple step.
Carry a safety mechanism that you feel comfortable with.
Bring emergency contraception.
In some countries it can be hard or impossible to get. Even if you don't think you'll be sexually active while you're there, it never hurts to be prepared.
Bring a selfie stick!
For those times when you don't want to hand your camera or phone to someone to snap a pic for you, the selfie stick will be your favorite tool.
Keep two hotel keys with you — one in your bag and one on your person.
That way if your bag gets nabbed, you're not locked out.
If you order room service or something from a hotel, never identify that you are alone.
If you have to, say the other person will "be right back," or open the door only partway.
Leave the DO NOT DISTURB sign on your door and the TV on when you leave your hotel room.
This will deter thieves, who will think there’s someone in there.
Befriend female hotel/hostel employees.
Ask them for tips about getting around the area and where NOT to go.
Have the address of your hotel or hostel written down to hand to taxi drivers.
Doesn't hurt to do this for anywhere you'll be taking a taxi if you don't speak the language.
Arrange a private transfer from the airport when you arrive, especially if you're arriving at night.
If it's in your budget, this can make getting your bearings easier.
If you’re listening to music, don’t wear both headphones.
That way you can always stay alert. You can also wear headphones with no music on as an excuse for not listening to unwanted conversation and a way to eavesdrop and overhear anything sketchy that might be going on.
If you get lost, don’t look at your phone or a map in the middle of the street.
Just duck into a café or shop and check there.
Spring for a GPS if you’re renting a car.
Looking at a map or your phone in an unfamiliar place is dangerous and time-consuming.
If you’re driving, fill up your gas tank when it’s half full to avoid running low when you’re in a sketchy area (or a place with no gas at all).
Take your bag with you to the bathroom every time, even on buses and trains.
Always go in a train car that has other people in it.
On buses or trains, sit close to the front and close to other women.
Build a financial cushion into your budget so you can take cabs when you feel unsafe walking.
Snap a picture of your cab’s license plate before you get in it.
Both for safety and also in case you leave something in it: Having the license number makes it much easier to track down.
If you stop to buy tickets or anything where your attention is away, put your bag between your legs or in between your body and the counter instead of beside you.
That way it's harder to swipe.
Drink in moderation.
Know your limits. Keep your wits about you while you're having fun.
Talk to lots of people!
If you’re out and on a tour, or walking around, talk to people and get a sense for what’s happening and where. Plus making friends is the best way to see cool things you wouldn’t find on your own.
If you get in a situation where you feel alone and unsafe, start telling stories using “we” about your (real or imaginary) significant other.
It creates a sense of partnership and security.
Don’t feel guilty about saying no to anything.
It's OK to turn down help with your bags, an invitation to dinner, a shot of vodka from a guy named Boris. Don't be afraid to be rude if it means feeling safe. And trust your instincts about when to accept help. Sometimes a male escort is a good way to feel safe, and there are plenty of nice strangers who are willing and able to help you.