Talk to people & be friendly: This can be especially hard if you're shy. But being friendly doesn't mean you have to walk around school wearing a t-shirt that says, "Hey, don't you want to talk to ME?" It can be as simple as smiling at people when you pass them in the hallway, or saying "hello" to the person next to you in homeroom, or complimenting someone on her new haircut. If you're open and seem easy to approach, you'll become the kind of person that others want to be around.
Learn how to listen: Did you ever notice that most people love to talk about themselves - their favorite sports, their hobbies, their dog...whatever? If you're a good listener, you'll be surprised at how many people are drawn to you. By asking questions and listening carefully to the answers, your new friends will feel the genuine interest you have in them. And they'll want to give it right back to you.
Let others know you like them: How many times have you been involved in a misunderstanding because a friend got something completely wrong? The same thing can happen with potential friendships. Sometimes people assume we don't like them, so even if they really do want to be our friend, they figure we're not interested. If you've found someone you want to be friends with, let him or her know. No megaphones necessary. It's the little things that count: saving a seat for your friend on the bus, bringing in an extra cupcake for lunch, or remembering to wish her or him good luck before a big exam.
Put your new friendships on "project status": If making new friends is something you really want, then you have to make it a priority. Just like improving at a sport or getting better grades, making new friends takes time and energy...but this is one effort that's sure to pay off.
Be patient: Friendships that are formed in a day sometimes last just as long (or short!). Developing solid friendships can take time, but that's okay. The more time you both spend getting to know each other and building a solid foundation, the less likely your friendship will crumble at the first sign of trouble.
Stay tuned for advice on what NOT to do when making new friends...!