In my experience, students  have never been brilliant at checking their school emails, especially the older kids. This makes communicating with them quite difficult when they are not sat in your class.

A great way to improve this is to use Facebook groups. Now, this presents a problem. The main one being schools tend to be terrified of social networks. Possibly because they do not understand them? However, if you have a forward thinking school, you can overcome this by showing them how useful they can be. Once they are aware of this they may let you give Facebook groups/Twitter a go.