Please ensure whether the project is RERA(real estate regulatory authority) registered or not. A RERA registered project is much safer than any other project as the buyer will get heavy compensation in case of a delay in delivery. Apart from that get an advocate to thoroughly read the Builder buyer agreement so that you can check what is your remedy in case of default of the Builder.
In case of any clarification please let me know.
-Advocate Mayank Patni