The three most common approaches include:Cost approach: An estimate of the replacement cost less depreciationIncome approach: Calculation of estimated potential rental incomeSales approach: Uses comps of recent transactions on similar propertiesBe sure you are leveraging the tax incentives availableIdentify any applicable tax incentives available for commercial properties - historic tax credits in certain areas, opportunity zones, environmental sustainability, etc.Understand available tax deductions, credits, and rebates - Tax deductions decrease the taxable value of a property, tax credits directly reduce your tax liability dollar for dollar and tax rebates are a refund of taxes paid under certain conditions.Utilize a cost segregation study - Cost segregation allows you to reclassify assets into categories with shorter useful lives, therefore accelerating depreciation and creating tax savings.Leverage energy incentives and deductions - Look into the Section 179D deduction and how you can save on tax by meeting certain standards to make your property more environmentally friendly.Best practices for commercial real estate owners and monitoring their property tax regulations:Plan proactivelyWork with a professional to receive guidance on complex regulationsUtilize specialized software tools to drive efficiency and compliance.What questions do you have regarding property tax valuations?

Quote from @Carlos Ptriawan:  They believe that they will increase the properties NOI by 45% over 5 yr hold, mostly through rent increases after doing 5K interior upgrades in all 252 units, thus adding 19 million to value of property. how is it possible increasing rent 50% in 5 years period in place where comps and rent is decreasing, this local market is extremely saturated.For me if I have to buy in Austin I would find complex that could give DSCR 1.3 at least with 80% occupancy.if they increase rent 50% then we should do intelligence on their closest neighborhood's rent. 

However, getting from simple Phase I/II due diligence to developing a remedial plan can be a large and complex process and costs would have a wide range until more is known.

I have one 57 unit in Mentor, 8 apartment complexes in Painesville too.  

I think @John Underwood is right @Vittal Premachandran.That question is a bit complex for most of here.

As you mentioned the city is extremely block by block and quite complex.

In a partnership, you'd still have liability protection, and you wouldn't have the additional tax complexities that come with operating as a separate business entity.

That's another complexity.

The STR Loophole is very complex, but can save you thousands.- Did you materially participate?

They specialize in tax, but the barrier to entry is much lower than a CPA, so they might not have the same level of expertise in complex matters.