There are a ton of free resources across all Biggerpockets & online I highly recommend utilizing.Also there are a ton of real estate related events here in OKC I'd recommend!

It's relatively affordable, but you can only report late rent and late fees(fines and other damages you need a judgement) .They also have to be 30 days past due.

Don't negotiate with tenants as it relates to what is in the lease agreement or what is not. 

Go over all the related documents again; ask for proof of anything you question, and if still on the fence hire a CRE to do an analysis.  

Tenant Default: 0-5% probability of eviction or early lease termination.Section 8: Class A rents are too high and won’t be approved.Vacancies: 5-10%, depending on market conditions.Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Class B Properties:Tenant Pool: Majority of FICO scores 620-680, some blemishes, no convictions/evictions in last 5 years.Tenant Default: 5-10% probability of eviction or early lease termination.Vacancies: 10-15%, depending on market conditions.Cashflow vs Appreciation: Typically, 1-3 years for positive cashflow, balanced amounts of relative rent & value appreciation.Section 8: Class B rents are usually too high for the Section 8 program.Class C Properties:Tenant Pool: Majority of FICO scores 560-620, many blemishes, but should have no convictions/evictions in last 3 years.

What helped me the most was getting forum backlinks on niche topics related to real estate investing, like here on BiggerPockets.

I am not even sure that this is STR related.

When able to purchase one for a very low price, spend the relatively small amount necessary to get a “clean” rating, and sell the property for maximum value. 

The MLS using a relator How did you finance this deal?

So that is for the listings as such.In relation to your question of things to know as a new investor, the most important one is that you generally (there are exceptions) have to purchase these properties in cash.