but the $7000 to pay off the vehicle will only save me about $600 in interest whereas investing that 7k into another home or renovations, like adding a new bathroom to my current 3bed 1bath home, would yield way more than the money saved.

Portfolio lenders use more of a DSCR analysis to lending - meaning they are likely to lend to you as long as the investment can pay its debts - more so than a residential lender. 

Don't wait for the perfect deal to come up, the most important thing is to get started.

For us, there was really no way to prepare other than making sure we were ready in case we needed to evict if they refused to leave, and then planning for but not hiring contractors until we were sure they actually left. 

I found a different insurer later that was $3k less.

Also, I had no credit score here in the US, so it was difficult to get a loan.

Fix and Flip where work will not begin for more than 30 days.     

We go into this using the buy and hold strategy so I'm perfectly fine with my capital being locked in for the long haul.  

As we all know business is about growing, but a lot of business die from eating too much than starving.

but generally speaking this is a good list and far better than what we see where folks get snookered by fakes who are being told what they want to hear and risk up front money only to lose it.