Trick to send mail in Future

First Download the Software Boomerang from www.boomranggmail.com

Then, go to compose mail and then to the option (Save now and then to Send Later) and you can choose the duration at what time you want to send mail.

And now, your Message can be sent. In case, if you want to reschedule or make any changes you can click on Boomerang and do the rescheduling