I usually just go on my own. I have a crazy work schedule and so do most of my friends. Coordinating a trip in advance is difficult, but I don't think I've ever gone on a trip and not met someone to hang out with along the way. It's a great way to make new friends.

My "crutch" is that I carry a camera. I feel more comfortable being alone if I am taking pictures, and I can always start a conversation by asking someone to use my camera to take a picture of me in front of something. I've met some great people and I've met a few people that I've gone on other trips with.

You might want to ease in by signing up for a small group tour. There's no reason it should be all women. You can hang out with couples or other single people once you're travelling and you don't have to find the "perfect" companion because you can spend time with different people.