There are several ways to increase the chances of extending the lease of a good tenant. The main thing to remember is to maintain an attractive price.
The chances of retaining your current tenant is much greater if the price the current tenants are paying does not increase. Over the years, we have seen minor increases in rent (even as low as $50) chase tenants out.
At renewal time, remember the old adage of a bird in the hand being worth two in the bush. Keep in mind that losing a good tenant will mean lost rent during the vacancy time and turnover costs . Also, you are never guaranteed that the next tenant will be as good as the current one regardless of how many steps you take to qualify them.
If your current tenant is on the fence about whether to stay or go, you can offer an incentive for the first month. Usually, a $200 deduction off the first month's rent for a 12 month renewal will help to persuade the current tenant to stay.
Another option that will benefit both you and the tenant would be to offer a property upgrade such as professional carpet cleaning. Doing something like this will not only help maintain the property, but will also show the tenant that you value their tenancy and care about the condition of your rental.