Best defense against queen's gambit?

play 2...e6 and then just act spontaneously 

Ok, that makes sense.

Go ahead and find me an 1800 player who hasn't heard of the queen's gambit, or a 1600 who doesn't know a few moves of the mainlines of the openings they regularly play.

Has davojwin been around since 2013? Anyway, possibly of interest:
Discovering Chess Openings
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf
First Steps: Queen's Gambit
https://www.newinchess.com/media/wysiwyg/product_pdf/7652.pdf

The Benoni

I know this topic is really old, but learning the classical lines is really great. Especially if you're making yourself deal with e.g. isolated pawns and/or hanging pawns. These structures (and their ideas) show up in all sorts of middlegames, so even if you end up not playing 1...d5 against 1.d4 I think it's worth learning something, and playing some games in, the classical QGD lines.

I like the Albin counterattack

Have you ever tried the lasker trap in the albin counter gambit. If you havent you should take a look at it:https://www.youtube.com/watch?v=kbyV4CZp_i4&t=0s

You should also look at this trap:https://www.youtube.com/watch?v=yZvyGs193QQ This is known as the elephant trap. 

There are other traps such as the cambridge springs trap that are also good. 

You can search up how to play against queen's gambit. There should be some things you can look into.

I think the Queen's Gambit Declined and Meran are good starting openings (and ending openings if you want as many of the world's top players use these in key games). So play d5 (unless you play the French, then e6 first is fine).  The big difference between the Queen Pawn and King Pawn opening is the c-pawn can advance without weakening the king (in fact, it unleashes the queen allowing Qc7 Qb6 or Qa5 in some lines).  So unless you're being funny, don't play Nc6 (this is nonintuitive) until after you have moved the c-pawn up two (or if playing c6, put that knight on d7).  The other big difference is the idea of Qb3 or Qb6 which comes up a lot, so start checking out lines where you or your opponent do this, especially if the queen's bishop moves out.  If you want to know more about these structures, review games by Capablanca on both sides and see if you can guess his moves.  It's not the most modern theory but it will mimic games up to the 1800's and give you strategic understanding that you can use for the rest of your career. 

There is no best opening, but there are certain openings that are best for beginners/improving players. 

Richard Reti recommends in his book "Masters of the Chessboard" that beginners should play the open games, because tactics is the foundation of positional play. That's why beginners should play 1. e4 and 1. e4 e5 as black. Against queens pawn opening you should just play 1. ... d5 which puts a pawn into the center and is therefore easier to grasp then the king's indian defense where black doesn't occupies the center in his first moves.

Based on that quote there we can recommend concrete openings to a beginner.

For White there are many possibilities which will teach a beginner a lot about tactics, opening play, attacking play, keeping the initiative etc.

Note that some of these openings like the nordic gambit aren't meant to be played forever. They just serve as a learning tool to understand gambit play, tactics.

As black:

I am a player rated around an average of 650 in live chess. What is the best option for me, I was recently thinking to study opening but the comment above is saying not to. So please suggest me the best way to improve my chess game. By the way my goal is to reach the rating of atleast 1000 till October in 3 increment 2 blitz games

I'm sure this is correct, since the poster is a titled player, but - can anyone explain how moving the c-pawn in a King pawn opening weakens the King?

The most important thing is to blunder less frequently. Also, do you know what the pieces are worth?

What he meant is that in KP openings, after 1. e4 it would weaken the King's defenses to move the Bishop's Pawn up beside it  with 2. f4.

But in QP openings, after 1. d4 the Bishop's Pawn may be safely advanced with 2. c4 without compromising the King's safety.

What is the importance of getting two Pawns advanced side-by-side? They cover a whole swath of adjoining squares (eg: d4+c4 cover b5, c5, d5 and e5) and thereby suppress the opponent's piece activity. Each Pawn also guards the square in front of its neighbor, which can be useful.

Thanks @bleemu, that makes sense and I agree that that is almost certainly what he meant.

Nimzo-QGD

It's not clear to me, why don't you play b6 to free your other Bishop if White plays Bxf6?

It's a line.

Black does better in the Bxf6 line by playing c6 (instead of b6) and freeing the c8-Bishop with the Nd7 / dxc4 / e6-e5 maneuver.

I started studing openings from 1300. Don't waste yourtime, Just play analise each and EVERY SINGLE GAME! Find the move where you did wrong - if it is a misclick, double check waht your gonna move before you move the piece with your mouse, if it is a hanging piece, make sure to check each piece's status in each position. If you genuinely follow these steps, you will get to 1400 pretty quickly

Thanks, that makes sense - Black want to play e6-e5.

Am I right in thinking that the reason Black plays for e6-e5 if White has played Bxf6 is that Black now has his dark squared Bishop already controlling e5 and also White no longer had a dark squared Bishop? So e6-e5 has become a realistic goal for Black?

It has become more realistic, yes. Also, Black's Bishop pair is increasingly relevant the more open the position is... and the exchange of Black's f6-Knight has lessened his pressure on the light squares, which makes b7-b6 (further weakening the light squares) less attractive than c7-c6.