Of course the co-signer should be significantly stronger in ALL areas as compared to the applicant...usually this is a parent or relative, and they should be well established, with ownership of real estate for years; long and stable employment; no, or very distant, criminal and traffic court records; well funded SAVINGS/IRA's or stock market accounts.

It also depends on the situation sometimes a HELOC is warranted for short term financial needs so long as you have a plan to get back in the same or better financial position afterwards and the "means," and "will," to carry out this financial or mortgage plan- HELOC's are typically full documentation qualifying loans so you'll need actual income to qualify whether it be from pension, insurance, rental's, etc that are all fully documented on taxes, W2's, 1099 forms, etc.

I am not saying you have to find a way to get a $100k/yr job, although that wouldn't hurt, but a stable W2 salary is going to help a lot. 

An additional benefit of a detailed engineering-based Cost Segregation Study is that it can increase potential insurance premium savings as well as provide support for the property tax appeals process.

As others have said watch out for property taxes and home insurance too. 

What about taxes and insurance, how much are those?

Make sure you’re checking in on your tenants, getting them to document any damage, and having solid insurance coverage.

Is your DSCR ratio greater than 1-meaning are you cash flowing (according to the lender's criteria of mortgage, property taxes and insurance (and HOA) if applicable).

The GP was so open and transparent every step of the way with the different types of insurance that were essential, adjusters, replacement cost, debris removal, code upgrade, etc.

To save money, management raised the wind and hail insurance deductible from 5 to 10 percent.