What all things I should look for while buying flat in gurgaon?

I am a software engineer and wants to buy a house to settle till I retire. I have specially looking for 3BHK because I will be having a family. Preferably ready to move property because I don't want to pay rent till possession date. I got some brokers number but doing it for the first time and need some guidance because I am not from Gurgaon.