As a buyer or investor (commercial or residential), first consider the title related issues of the property concerned.

Avoid taking possession of a property where title has not been secured, either individually or in the name of a society.

Ensure that the property complies with applicable laws by asking for certificates such as completion, occupancy and no objection certificate (NOC) from appropriate authorities.

Also check whether the property is embroiled in any litigation. 

If the investment is in a unit (not the entire commercial or residential complex), the unit holder must ensure that he has an equal right vis-à-vis other unit holders in the same unit. He should have the right to unanimously decide without the involvement of other unit holders about the sell/mortgage of his unit. 

All buyers/investors are required to pay appropriate stamp duty. 

The sale deed must be registered with local authorities within 4 months of execution of the deal.