Start with Jim Dahle's "white coat investor" website and Youtube channel and Reddit subthreads.

You should avoid any syndication that's advertising in social media (or even in crowdfunding website).Why ? 

Does the FF website work for you? 

They were month to month when I bought the property, but I never increased the rent since they were good tenants in the beginning.I already paid for a lead inspection and building inspection for the property via the city of detroit's website, so I know what the condition of the property is in and what repairs are needed in order to get it certified.

By chance have you checked out the BiggerPockets property management finding tool on the website?

They have a lot of free info on their website as well. 

When to outsource it?

An example problem statement that I may have stated (and built the software for) in 2003, when I started investing full time: Build a tool for lead generation that collects county records from the county recorder's office (and property card data), finds the recent first mortgage defaults  from trustees websites or public filings for properties that are between 1000 and 1700 square feet, in a neighborhood of 90% like-kind properties with greater than 20 parcels, houses built after 1978, that can cash flow at current rates when fully leveraged. 

Also, check out out website easystreetcap.com to see testimonies from clients about their experience with us!

I would recommend attempting to obtain the contact phone number independent of the number that the tenant provides, i.e. website of the property.