I liked what my old apartment did when our lease was up: They sent us a letter offering to renew our lease at $10 more a month if we renew for 12 months, or $30 more a month for 6 months, or we could go to month-to-month for $60 more a month. Your numbers may look different but that would reward your tenant for renewing their lease while still raising the rent a bit. Plus seeing that our rent could go up by $60 softened the blow of the $10.
Maybe ask for the full $300 to go moth-to-month, $200 for 6 months, and $50 for a full year lease? Just a thought...