Starting Out, Planning

[Fletcher Caulk]

I'm a relatively new real estate investor (have one property that I kept after moving out and looking for turnkey rental to purchase within the next two months). 

I want to better understand tax and legal considerations for my current / short term situation and how to set myself up for success in my future plans of owning a large portfolio of rental properties. 

What tax deductions should I be looking for outside of the obvious (interest, property management, HOA, depreciation, etc)? Do I need a tax professional with just the single property if I'm using tax software (H&R Block)?

On the legal side, is there anything to consider with my current property? How critical is it to get legal advice if going through a professional turnkey provider/property manager? 

Are there any considerations to make now that will make things easier as I scale? 

I realize I have many questions, even if you have advice on one of the questions I'd love to hear it (with the understanding that tax and legal advice will ultimately need to come from a professional)!