With Google Apps for Education there are a number of exciting tools that can be used to enhance teaching and learning. My advice however is to start with Google Drive (my drive when you login).
One document can be viewed and edited by several people at the same time.
Let students access homework tasks and subject resources by putting them in a folder in Google Drive and sharing it with the class so they can view. It will appear in their Google Drive in "shared with me"
Homework/project tasks can be structured by creating a proforma in the shared folder that students can view. They can then make a copy of the document and fill it in making sure they share it back with you as their teacher. You can then collect together their work which will appear in your shared with me area on Google Drive and follow their progress commenting on their work as they go.
Once you have got started here are a few must have skills for teachers using Google Drive from Med Kharbach's blog that you can aspire to use with your classes.
Technology for Learning Lead Practitioner