Clearly identify what you want to achieve in real estate and use that as a guiding force throughout your journey.

Start by reading the Ultimate Real Estate Investing Guide: https://www.biggerpockets.com/guides/ultimate-real-estate-investing-guide/introduction2.

Many experienced mentors in this group can help guide you in the right direction.I highly recommend saving as much as possible and setting aside a hedge fund for financial security.

I worked with an expert STR agent, Troy Nowak, who guided me through the purchase and negotiation process.

Start with BiggerPockets Ultimate Beginners Guide (free).

Most importantly, how can I set realistic, effective metrics to guide my investment decisions?

Hi @Bien Nguyen, @Josh Green is the go to realtor/investor here in Florida for all your STR needs and will be able to guide you towards making a successful investment/purchase.

With this, they should be able to guide you down the right path.

TurboTax has rental property features, and the IRS has a great guide on rental income, deductions, and recordkeeping - IRS Rental Property Tax Guide.https://www.irs.gov/businesses/small-businesses-self-employed/tips-on-rental-real-estate-income-deductions-and-recordkeeping2.

Ok, yes that's a bit cheeky but seriously, your talking about some very important, regulatory/law stuff, if your not willing to do the most simple basic actions of simply googling the laws, and reading through the statutes, I am sorry but than my time and effort has not been earned to help guide.