Study! It can be boring, but you need to study if you want to be smart.
Read non-fiction books! You will learn new things by reading informational books. If reading nonfiction books is extremely boring for you, read online articles or just read fictional books and still learn new words.
Listen up in class! You need to be paying attention if you're going to learn anything and become smarter. If you're sitting beside someone that you either usually talk to or he/she is talking in class to the point where you can't pay attention, talk to the teacher about getting a new seat. If your teacher says no, tell the person to be quiet.
Be a good leader.
In a group project, take charge! Sit down and tell everyone to give their ideas. This way, you'll be able to have everyone speak, and they'll know subconsciously that you are capable of being the leader. After everyone has given their ideas, give your opinion of the ideas and let others speak their opinions. If you are really against the idea, have a vote and see who is for and against the idea. Sometimes, the leader needs to let others get their way. Then, ask the group who wants to do what. If there are two people who want to do the same thing, let someone work on half of the task and the other person do the other. If this is not possible, it's best for either you to choose or to have them simply do rock paper scissors. If there are tasks that no one has volunteered to do, even if you don't want to do it, say you'll do it yourself. If there are more tasks than there are people, take up the extra tasks unless someone else offers to do them. Finally, get everyone's phone numbers so you can call them and be sure they are working on the project and to get a report on how they are doing.
If there is someone without a partner or not in a group, offer to let them join, even if they are a so-called "loser". This will make the person feel accepted, and you will, even if it's not at the moment, feel good about this decision.
If there is someone that is not completing their task, don't be afraid to confront them and tell them to get their game on! If there isn't much time left for the person to do their task alone, offer to go over and help them! There's nothing worse than when someone doesn't get their task done and everyone ends up with a bad grade after all the hard work they've done.
Be approachable and friendly.
Give out compliments! Don't tell fake ones, though. Be genuine! They will take you more seriously and feel much better about the compliment you gave them.
Be sure to have good hygiene! Nobody is approachable when they smell! So be sure to brush your teeth twice a day, brush your hair, wear deodorant (very important), and take a shower every day if possible. Also, wear clothes that fit you!
Always have a smile on your face and good posture. A smile makes everyone feel happier, especially if it's directed at them. Be sure it's not fake, though, or they will be able to tell and will feel sad and think you are being "fake nice" to them. Good posture tells people that you have confidence, and that makes people feel comfortable around you.