Hi Pushpendra,
You're doing great with the mapping! However, please take extra care to outline the building's structure accurately and use 'Q' or right-click to select 'Square' for better precision.

Here this guide on "How to map buildings accurately", do check it out: https://docs.google.com/document/d/1Swwz-ZwM3_YOstqstsmCg1-lNAPbnMLpi1Al-h-2UOQ/edit?usp=sharing

Thanks,
DurgeshSinghChouhan