create responsive (mobile compatible) template for email

we send emails from a Windows serer using [login to view URL] within ASP Classic code. Attached is sample of what our current build is - basically just use a table to form the email. Client is wanting to make the emails mobile compatible - responsive - so they work regardless of the device or screen size it is being viewed on. I just need one sample email then we will apply to the rest of the emails from there. Any ideas for improvement are welcome. thanks