First of all you have to understand that this is not an overnight process. It takes time and focusing. I will say what you have to do.
1) Read news paper daily for at least 30 minutes. Try to read editorials and opinions columns also.
2) If you are a regular user of facebook, then like GK pages, quizzes, writers and politicians also
3) Download apps like, prep, IAS, Iasbaba, GK etc
4) Try to get company with people above your age, who were having work experience in any field. ( I suggest 40+, as they talk less nonsense ;).)
5) Read books, means whatever books you get. Make it as a habit. eg- magazines, manorama year book, self helping books etc..
6) Try to avoid filmy gossips and other time killing entertainment or else you will regret it later.
Above all what you need is that DESIRE for knowledge. You may heard this saying - "When the student is ready, teacher appears."