Practice handling common objections and how to overcome them on a daily basis. 

To play devil's advocate, that's objective data in the public record versus OP's referenced map being opinion.GreatSchools.org, which if they are 'grading' the schools would be opinion, also isn't a licensed real estate professional (I assume).

(a lot of Americans are not ready for accepting foreigners as "credible" yet... sadly), and that they can handle seller objections, and have a full understanding of seller concerns, your market and the workings of your business.But yes, I agree with you.Looks like you all are getting really serious and successful.

If the tenant is paying significantly below market rate, you could make a case for an increase, but ensure that it's fair and justifiable.Offer Renewal Incentives: Consider offering the current tenant an incentive to sign a new lease at a higher rate, like property improvements they value or services such as yard maintenance.Tenant Replacement: If the tenant decides to move due to the rent increase, be prepared to rehab the second unit and find a new tenant, ideally at a rent that reflects the current market rate.Remember, with long-standing tenants, especially those who are elderly or on a fixed income, it's crucial to balance business objectives with empathy and respect.

More properties, more problems, but if you have the funds to do it and cash flow is the only objective, this could be a good way to maximize your cash flow. 

The object is to get big enough that you need property management.

Recommend you do a lot of research on your own.I would recommend the following based on your post if these fit with your objective.  1.   

I think that's very fair, and I can't see any judge objecting....

No system is perfect, so don't waste your time chasing after the next shiny object.

No system is perfect, so don't waste your time chasing after the next shiny object.