I would suggest a good PM to start if you don't have a solid background in hospitality or at least something in the service industry.Self-managing can save a ton of money if you know what you are doing. 

I’m also the founder/owner of Sabino Properties, a boots-on-the-ground services provider in Dothan, AL and the Wiregrass.  

Can you spend money on a CRM, automations, VA calling service, a VOIP phone system, etc?

The general rule of thumb when using debt is to ensure that whatever asset you buy with the debt should make more than the debt service.  

Since acquiring a four-unit property on the Northwest side, my bi-monthly bill has typically been around $500.

Assuming you have access to MLS (Multiple Listing Service, a place for agents to list deals).1) Look for deals that look like investor-type of deals (e.g. low purchase price, ugly houses, or sometimes MLS will even say what type of financing it is)2) If the buyer's info is there, voila.  3) Otherwise, contact the realtor to look for leads (that will be more of a uphill battle, but you never know...)

any lender wants to know how you plan to service the debt.

@Ming HuangRecommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

@William GranthamThank you for your service and welcome to BP.

Typically HELOC is much cheaper than hard money.