Part five of How to be a Great Tenant touches on your rent.
Pay your rent on time. Many tenants believe they have a "grace" period. Most leases will not charge a late fee until three to five days after the due date. Though this appears to create a grace period, it does not.
If you pay rent three days late every month, you may never incur a late fee. However, when you move out and you need your landlord's reference, he can state you were late every month on rent. Make sure to get your rent in on time.