First, you need to do your research. Look at comparable listings. What is the minimum night stay?
There is also software that can help with this and save you time.
Also, look at the booking window. Are you trying to fill for next month or 3 or more months away? As the dates get closer, you may want to bring down the min stay. You want to set up orphan days to rent the days in between. For example, you have 3 days available in between two 5-night stays. Set it up so guests can then book those 3 nights to help fill the calendar.
Here for any questions or advice
John L