My schedule was about 1-2 hours in the morning and 1-2 hours in the evening during the weekdays and rigorous studies during the weekend. Also, I tried to write one Full-length test every week (Included AWA only in latter half).
One work-plan that has worked for many of my friends can be found at this link:
This isn't my prep-schedule. This includes fixes for the mistakes I made while preparing. I know many of my friends and followers of my blog, who followed this work-plan and got 750+ scores.
See question on Quora