How can I hack a particular website?

There are no direct ways to hack into a website. Keep in mind that hacking into a website means gaining the administrative access. There are no tools or programs giving you direct access to the administrative panel. Below I will list some common methods people utilize to hack websites.

Finding Vulnerabilities and Hacking Yourselves -A website is often hacked by finding a vulnerability in it or it's system and then exploiting it. It is often hard to find manually and hence, you can use a tool like Acunetix Web Vulnerability Scanner that lets you scan any website and find all kinds of vulnerabilities on it. Then what you have to do is try and exploit the vulnerability. You can try and google to find how to exploit using a particular vulnerability or use exploit databased like Exploits-db or 1337Day to find the right one. Please keep in mind that it can be an incredibly long process the scanning of websites. And it is usually quite hard to take advantage of low level vulnerabilities. You should always try and use the high level vulnerabilities and move down which will give you the upper hand. 

SQL Injection -A study in 2010 shows that 91% of the websites out there are vulnerable to SQL Injection. SQL Injection is one of the most popular and commonly used type of web penetration method. Using SQL Injection, you are able to retrieve sensitive information like administrator accounts, database informations etc. This method utilizes SQL Queries to retrieve information from a remote website. You can follow this guide to become better at SQL Injection and learn some queries at the same time. There are hundreds more tutorials explaining various types of SQL Injection like Double Query, Blind SQL Injection, Time based Injection etc which you can easily see using the search button. Try to learn each attack one at a time. 

Cross Site Scripting (XSS) - XSS or Cross Site Scripting is another attack method used to hack into websites. Using this attack, you are able to execute HTML and Javascript commands on a website using queries. Using this type of attack, you can steal cookies from the administrator and get lots of information. Usually, a hacker would setup a Cookie logger or a stealer on a vulnerable website to get all details possible. The XSS Tutorial by Zer0Pwn is excellent for beginners to learn and understand XSS attacks. You might also want to learn basic HTML and Javascript since it will help you in the long run with advanced XSS attacks since you'll have a basic idea how websites run and how one component interacts with the other in making the website functional.

Local File Inclusion(LFI) - Local File Inclusion is yet another method you can use to hack into a website. It gives you access to read remote files on a server through your web server. This is also a very popular and easy to exploit vulnerability found on web systems. It is fairly easy to learn and you can try it on your target website.