Step 1: Do your homework
If you have a problem with a specific task, try asking for help in the end of class or in an email. Many times your teacher can help you a lot more than a parent could because the teacher knows exactly where the class is and what some common problems are. A parent, although trying to be helpful, may not be very good at helping because they are at a much different education level and therefore know things that will really mess you up.
One of the tricks to completing homework is dynamic time management. This means that instead of doing exactly what the teacher tells you to do, only do the stuff you have a problem with. An great example of this is math homework because quite often you will receive a large number of questions that may be deterring. What helps is to only do the things that you have a problem actually doing rather then every single question. This is a much more effective homework strategy because it gives you the time needed to work on everything else that you may have a problem with.