Exactly how do you get better at chess?

foolsmated is right. Just have fun. Having fun and enjoying chess will lead you to get better. 

Try posting a 30 min game with your annotations in the game analysis forum (preferably a loss or a long-game). This exersise will certainly aid your thought process and some higher rated players may offer some words of advice.

by going to jail

Realistically I think you have to work on these two practical abilities first.

First:
100% of the time, after your opponent moves, look at the new squares they threaten.  This includes squares the moved piece attacks and new squares pieces that may have been uncovered attack.

100% of the time, before you move, check if the destination square is safe and if the pieces/squares you necessarily undefended by moving that piece are secure.

And after you can do this for 9 out of 10 moves you can start thinking about the next ability.

Second:
This is harder, so just make a good effort to, 100% of the time before you move, you have already looked at every check and capture your opponent has available.  According to chess coach and author Dan Heisman there is no player under 1600 who does this for every move.

So now: 
1) if his last move didn't threaten to win, and
2) your intended move doesn't instantly drop material,
3) you check if your intended move is safe in terms of all the checks and captures.

This is hard to do at first, and may require only long games.  Even then you may find at the end you don't have enough time to keep doing this.  The good news is with practice it gets easier until eventually it's second nature.  Only at that point does knowledge in strategy, openings, endgames, etc start to make a difference.

If I ever figure it out, I'll clue you in. :)

play against a computer. use the takeback button. play until yuo get into a lost position then take back util you have an equal position. then start over.

Keep things very very simple - always have a reason for playing a move, if someone says after a game 'Why did you play that?' and you can't answer it then something is fundamentally wrong with your thought process.

One very simple question to ask yourself before every move is 'How can I improve my position?' Don't burden yourself with over complicated plans, concentrate on developing your pieces and fighting for control of centre squares in the opening. Once you have castled and have your minor pieces developed work out which are the best files for your rooks, beginners often forget to bring their Queen side rook to a more active position. Try to figure out what your opponent is up to, if you can't see a way to improve your own position ask the question from the other point of view 'How can my opponent improve his position?' Then work out a way to stop him doing what he wants, that can be just as effective as doing something positive for your side.

This involves more positional than tactical thinking but its much more satisfying to play a game with a real strategy than just making one move threats that are easily answered all the time.

If you are making no progress, you can always hire a coach to pinpoint your strengths and weaknesses. Have a look here.

Since you solve chess puzzles, but still commit many simple blunders, your problem is thinking process. Simple tips to address this.

1. Always look look at the whole board.

2. Always study your opponent's last move.

3. If there are moves that requires calculation do it.

4. You should not only look at your possibilities, but your opponen as well.

5. Beware of tactics.

Another thing study endgames, study endgames alot.

keep playing with better players on good sites (for example chess.com) rather than some stupid platforms of China local like QQ or ourgame.com. 

Under 1000 level which opening you play really doesn't change a thing other than you might like certain kind of positions more than others but that is that.

I'd suggest:

1) Learn opening principles and apply them in your games best you can.

2) Study tactics. Study them so much that knight forks are obvious tactical pattern to you, study them until you don't leave pieces hanging, study them so much that you see every mate in one in every situation ever, study them so much that you don't blunder backrank mates and list goes on. The fact is that this really is the fastest way to improve as a chess player. Many beginners waste endless amount of time looking at openings that no one isn't going to play correctly at your level and with right approach it would be possible to punish them for that but it isn't going to happen without tactical knowledge. So by getting better at tactics you also improve your opening play.

3) Endgames. Learn mate with: King+Queen, King+Rook

How to get better at playing chess...

PLAY MORE GAMES. Play people that are very good watch how they move.

Check out the tactics trainer

I played chess when there were no wonderful tools as players have now.

1. use the tools--especially tactics trainer.

2. play the toughest players you can. always try to play against players at least 200 points above your rating. You will learn from this.

3. After the game is over you can use a chess engine to find what mistakes you made.  try not to make the same mistakes in the future.

Don't listen to this guy. He's playing with you. I can explain. Or someone else can. He is intentionally giving you very, very bad advice mixed in with some good advice. I think it's intentional. Anyway, only some of what he said is correct. Feel free to PM me.

Hire me as a trainer.  I have very reasonable rates.  Also, read Chess: 5334 Problems, Positions, and Games by Polgar from cover to cover.  Contact me when you are finished.

If you are below 2000, do tactics problems like a mad man until you solve all of them. You can do them at chesstempo. Play long games, preferably 15 min games. The slower you play, the faster you improve.