Checklist for play

I'm not a beginner, but I'm not a good player.  I blunder often.

If anyone can help me with a kind of checklist of things to go over before making a move, I would appreciate it.

So far I have the classic: Checks, Captures and attacks

to which I have added, "check for any hanging pieces (which is kind of covered by captures), but I would like to hear from some experienced players on things they check prior to making a move, so that I can stop making these awful blunders.

My anti-blunder checklist is just

What does this move achieve?

What are the weaknesses of this move?

What was my opponent's plan or threat?

And then I calculate the lines of what my opponent will do to stop my plan if I have one.

I am human, I will make the mistake of losing. If I am low on time I must depend on my intuition.

@3

It is better to be low on time in a winning position,
than to lose on the board with time left on your clock.

Fischer blunder checked even in 5|0 blitz. See his note to his move 30:
https://www.chessgames.com/perl/chessgame?gid=1044673

Tips

How To Find The Best Moves And Not Blunder

Mine is:

What do they want by playing that move?

How did their move change what squares are controlled or what lines/diagonals open or close?

What are at least 3 candidate moves (even if it feels "forced" like a simple recapture)?

For each candidate move, what squares are controlled or what lines/diagonals open or close?

For each candidate move, what will they play in response (is anything of mine vulnerable or hanging, is my King safe from attacks, sacrifices)?

There are good ideas above. If I can add anything, it would be asking yoursellf two things. Why do you win and why do you lose. This will help you gauge what needs work. At your level studying tactics will alleviate many problems such as dropping pieces and seeing what your oppnent might be planning. Knowing an opening or two with its middle game plans will also help you get a solid foundation to work on.

Slow down. Every blunder is a direct result of playing too quickly.

King Safety

Piece Coordination

Pawn Structure

Open Files and Diagonals

Development

Opponent's Threats

Time Management

Calculate Variations

Material Count

Plan and Strategy

Endgame Considerations

Review Previous Move

Maintain a Calm Mind

Blunder Check

Some of the advice above is way too complicated and not directed at players below 1000.

The important things:

• Stick with your checklist, it's classic for a reason.
• Play longer games (30 min) instead of blitz. Take your time staring at the board.
• Learn the basics of two openings, 1 for black and 1 for white. Czech pirc and jobava london are often recommended for beginners. Don't go too deep, just watch some youtube videos. Robert Ramirez worked for me.
• You've probably done so already, but if you haven't: do some lessons on tactics. Basic checkmate patterns, forks, pins, skewers, discovered attacks. Chess.com's beginner's and intermediate courses worked for me.
• Practice the concepts you've learned by doing lots of tactics (= puzzles). The puzzles on this website are fine. The Steps method (only on paper) is also good.

Some psychological advice that I have a hard time sticking to myself: don't be afraid of losing rating points. What goes up must come down but will probably go up again. When I couldn't get over this rating anxiety, I played games on another platform, where my rating meant less to me. After all, it's about practice and experience.