A good relationship between students and teachers makes the classroom a more inviting place. When you like your teacher, it's easier to pay attention to his explanations and improve your grades. When you consider your teacher a friend, you'll certainly have more respect for him. When your teachers consider you to be a friend and not only a student, they'll feel freer in class and that will probably affect the classroom in a very positive way. Now here are some tips to develop a friendly relationship with your teachers:
Ask questions. If you have any questions about that subject, ask them. Teachers like to teach and asking questions is the first way of interacting with them. Show them that you're interested in their subject. That will make them notice you. But never ask questions that you already know the answer to. If your teachers realise that you are not asking real questions, they might think that you're not actually trying to learn, but only trying to make an impression.
No need for compliments. Don't say things like "You look lovely today, Mrs. Lim" or "Did you lose weight, Mr. Smith?" Your teacher will probably think you're being false and only trying to get some advantage, and that's not what you want. Instead, you could do some innocent jokes (jokes that won't offend your teacher). The moment they start doing some of the same jokes (but towards you), then you'll know that your relationship is becoming friendly.
When you see one of your teachers in the hall, greet him and ask if he's going to that concert or if he's seen that movie. That way you'll show that you consider him a friend, and that's why you talk about common subjects. Some teachers don't like to have a friendly relationship with a student, but most of them want to have those simple talks with their students. And after a while, they will start to talk with you about non-school subjects in the class. That will make more students in your class get involved in those talks, and everyone will start to consider that teacher to be a friend.
The rest is totally up to you; it is very easy to develop a friendly relationship with any of your teachers. If you want to be friends with your teachers, just treat them as friends, but don't forget that no matter how good of friends you are, they will still be your teachers and deserve your respect.