I don't know your market but generally a good way is your local rental section in your newspaper. Another way is to look on the main rental website portal for your area. The third way is have an agent pull info on rentals through the MLS.
Don't look at what rentals are asking look at what they are RENTING for. Usually agents get first months deposit and the ten percent of rent. You would be better off hiring a property management company that has a pool of already qualified buyers that have been through a rigorous screening process. The property management company will also take monthly rents and keep accurate records whereas an agent generally just writes a lease. Some brokers will not allow their agents to do more than write the lease as the brokers Errors and Omission coverage does not cover property management because of the high chance of litigation.The property management company will also usually have better leases in favor of the landlord because that is all they do is rentals compared to selling homes.
When renting don't try to get the highest rent. What I mean by this is if your rent roll values for a home your size in your area go for between 1,700 and 1,900 a month you want to be between 1,700 to 1,800. The reason is just like well qualified buyers want a deal so do quality tenants. The higher rent payers are usually bad tenants who got kicked out of their last place for no to late payments and cause a lot of damage. It is better to have many tenants to choose from with a lower rent and get first and last months deposit then to rent high and have to evict a crappy tenant spending thousands in evictions costs and new carpet and paint to get re-rented again.
I wish you much success. No legal advice.