Gathering information
MALTEGO:
Maltego is a software created by paterva you go to this link for more information on paterva
Here you can Download the MALTEGO software according to your operating system and dowload and install it
After installing you need to register with paterva for using MALTEGO using simple steps register and activate your api key which lasts for few days, dont worry you can get a new again after the previous api key expired.
After logging in install all the transforms and you can drag an entity you want like person,email id,phone number,skype ID etc there are many entities from which you can search.
By this you can get information