Some things that might help when talking to them:

• Choose a good time to talk - If they are really busy or are upset about something then they are less likely to be able to concentrate on what you say. Sometimes it's good to wait until the person is alone so others won't interrupt you.
• Give them a reason to listen - Say something like "I really need to talk to you about something because it's affecting my school work".
• Be honest with them - It's easier to help if they know the full picture. Don't pretend that everything is OK if it's not.
• Write them a letter - If you don't know how to raise it you could try writing a letter to them. You could ask them to talk with you about it next time they see you.
• Tell them what you need from them - Sometimes talking about stuff can make it seem better, but if you need more then that, ask them to help you figure out what you should do next. Maybe you could go through this web site together and look for other people who can help you.