One of the things that I always like to do in that position is in crease it and if you find a really good tenant (after screening, and checking everything) offer them a small yet significant discount if they are willing to sign a 2 or more year contract. This is very convenient, in my opinion, because it helps you insure that you will have passive income for a longer period of time. Plus if you think about how much it cost you (lost of rent, fees,...etc) for the time of vacancy between tenants it definitely makes up for it in the long run.
Thy key is not go low enough to temp the tenant, yet stay as high as possible, where you still have. A good cash flow.
I did that on a unit 2/2 that I could have rented for $900/month, and if the tenant signed a 2 year lease I could do it for $850/month. The tenant has been there for 3 years now, he keep the unit spotless, and always pays in time without any issues what so ever.
In a yearly basis it only cost me $600 less than the rent. I made that by not having any vacancies.