But, this is now our 6th move so I have a few tips that I can sometimes get to work for me, sometimes not (in fact if you have any tips PLEASE let me know because I could use them).
1. JOIN! Find groups, join them. It doesn't matter if they sound stupid, or like something you wouldn't necessarily do, you won't meet people in your house (believe me I've waited, people aren't going to come to you). Women's groups, book clubs, baby groups, PTAs, these are all places where people come together chances are you will meet somebody there.
2. TALK! I know it's hard, but you have to talk to other people. It usually doesn't have to be witty or even clever. If you are overseas it's as simple as "how long have you been in XYZ?" or even "is this your first time living overseas?" you can follow that question up with "oh, where else have you been?" Being overseas gives you a great conversation starters. (this also works on your home turf too, but people might not have as much to say). You can also make small talk based on the activity you are doing, "do you read many books?" "oh is that your baby?" "what grade is your child in?" "What other charities are you involved in?"
3. INVITE! This is critical! You have to invite people out to indicate your willingness to be more than just acquaintances. You have to do this often, and early. It doesn't have to be fancy, Coffee, tea, drinks, lunch, pedicures, museums, whatever. Just an exchange of phone numbers isn't enough, just an open "we should hang out" is also not enough. You have to make a specific plan, and it's easier if you initiate it. Chances are, the other person is just sitting around wishing for something to do to, but they don't know that you are not doing anything either, and that you could be not doing anything together.
4. REPEAT! You might think, hey I've done it once, great. Now the people will start flocking to me. Sadly no, (or at least not for me--if you've had other experiences, don't tell me, I'd rather think it's this way for everyone and not just me) you have to keep putting yourself out there, and talking to people in order to get a group of people that you can hang out with. It's tiring, and can be frustrating, but it's worth it.... or so I keep telling myself.
**I would suggest you do this as soon as you get to a new place. I have had many many experiences, where I have found people who I think are really really cool, but I waited too long and I made friends with them as they were leaving.