Gathering Information before hacking website.
Before attacking(pentesting) a website we must need to gather some important value and then mapping the attack surface. If we don't understand how the site is working, what is available on the site, what type of input it takes etc then we will not be able to make a good attack(Rarely success without passing gathering information). Many skid exist around us who just start looking for SQL injection or start brute forcing the web form and at least fail .
Gathering information and mapping the site is very very important So i will explain(not very details) how to, what looks for etc.
Spidering the web:
Basically i look for links, web form, source code, directory etc.
There are many tools you spider target website. But I prefer a proxy tools such Burp suit,owasp-zap and a downloader wget .