@Nash Paul one piece of advice, you can accelerate your learning curve and minimize huge mistakes by working with/for someone who is doing what you want to do, so be on the lookout for someone you can add value to in exchange for being close to the action.

DONT take shortcuts and try to cheap yourself out of things. a big Mistake I made was that I trusted someone to manage my property for $100 a month while I Was out of state.

Thanks @James Bailey, my mistake, it's fl 32207, Spring Park.So, any feedback on this (correct) one?

Improperly calculating debt service, underestimating capital expenditures, and improperly forecasting future expenses, especially property taxes that re-assess at a higher value after acquisition are all common mistakes. 

You made the mistake of not having a trusted third-party as your eyes and ears on the ground, and now you need to deal with the repercussions of that mistake. 

Be prepared to take on a couple of mortgage payments.Typically, when buying from a turn-key provider, most of these mistakes can be avoided if the provider ensures that a tenant is placed prior to closing on the property.

I definitely want to avoid mistakes as much as possible.

You can then sue him for all the expenses including your lost rental income.Compassion is a mistake and will be very expensive compared to following the proper process to evict.

The less investors there are in the deal the less back office work involved (less time commitment, less room for mistakes, fewer resources needed, the list goes on).

I used the BRRR analysis, but believe there are errors in the way I entered the information and/or have made several mistakes and/or am probably not using the right tool...??....