How to stop blundering?

as long as I can see, don't play bullet. Try 10 min to have time to think. Also train puzzles

Hi there!

There's a few things you can do to avoid blundering in your games. These apply to all types of blunders, whether they be about hanging pieces, missed tactics, or allowing a forced checkmate.

1. Before you think about making a move, look at the board. Every time a move is made, something about the position changes. You should check to see if any of your pieces are hanging (i.e. they are isolated, attacked, and unprotected) and whether your opponent's pieces are threatening to checkmate you on the next move. Taking the time to do this will help you avoid making bad moves.
2. When you decide on a piece to move, ask yourself what it is currently doing and whether the position will change for the better, the worse, or not at all. For example, if a piece is protecting something more valuable or critical, it may be a good idea to not move it. Alternatively, if a piece is hanging, moving it to a safer square would be the better move to make.
3. Don't just look at your own moves. Every time your opponent makes a move, ask yourself "if they could play one more move right now, what would they do?". This will help you spot tactics and checkmate threats and allow you to adequately deal with them. If you only focus on your moves and your plans, you will blunder more often.
4. Related to point 1, when it's your turn you should always look for checks, captures, and attacks on your side and your opponent's side. This will help you determine the best move to make, or at the very least a move that isn't bad if you really don't know what to do. 
5. Do not give away material for no good reason. There is a difference between a sacrifice and just blundering a piece. If you're going to sacrifice a pawn, a piece, or your Queen, it must serve a strategic or critical purpose like opening up the position or going in for a checkmate attack that you know will pay off. Otherwise, you are just handing your opponent the win for free.

At its heart, not blundering comes down to improving your board vision and your knowledge of tactics. If you don't make moves "just because" and you do your best to avoid hanging pieces or throwing away material for no reason, you will blunder less frequently. The best way to practice this is to try doing chess puzzles and by playing longer time controls like 15|10 which give you the proper time to think (playing Blitz and/or Bullet constantly will not help you improve).

Finally, if you do blunder, the best way to learn from it is to analyse the game afterwards, isolate the blunder, understand why it is a blunder, and then vow to not do it again. In doing this, you will also spot when your opponent makes a blunder and you'll be able to capitalise on their mistake.

I hope some of all of this has helped! Take care.

- Logan