The most common answer, especially in recent times, is highly levered, floating rate debt.This is not the only answer, by any means. 

Your question is a very common question, and I can appreciate your concern here.

This is a very common issue in parts of Milwaukee and I have done lots of basement reinforcing on our rentals.

A common misconception is that you have to put down 20% of the purchase price.

This is a common 'trick" we use in flipping.

Are there any red flags or common mistakes investors should avoid when reaching out?

As remote work is more and more common, many professionals look for a home there.

Duplexes are very common here and are much easier to find than a Quad as well.

Learning from agents commonly working with investors is your next opportunity to find a mentor.To be honest, I wouldn't try to find a mentor from random investors on the internet.

If you research recent sales you can always provide the appraiser a list of those sales.One of the best ways to insure a higher value is to update the property using materials and fixtures that are popular and common in the area.