- Make sure all your pieces are safe.
- Look for forcing moves: Checks, captures, threats. You want to look at ALL forcing moves (even the bad ones) as this will force you look at, and see the entire board.
- If there are no forcing moves, you then want to remove any of your opponent’s pieces from your side of the board.
- If your opponent doesn’t have any of his pieces on your side of the board, then you want to improve the position of your least active piece.
- After each move by your opponent, try to think what your opponent is trying to do.
Blundering


GM Magnus Kingdom and IMBacon have posted beginner tip compilations which discuss premove checklist and a ton of other amazing stuff to improve beginner blunders. However IMRonilm1204 answers your question nicely.
I'm still a beginner myself, but for what it's worth I'd also recommend correspondence games until you have your premove checklist internalized and find your blunder count dropping. Also use the time to utilize the analysis board (engine off) to anticipate your opponents next move which will hopefully further improve your move choice and anticipate their plans/counter threats.
https://www.chess.com/clubs/forum/view/tips-from-me-highly-recommended-chess-tips-chess-tips-to-all-my-followers-2
https://www.chess.com/forum/view/for-beginners/imbacons-cheat-sheets
GM Magnus Kingdom blatantly copied IMBacon and said he made it up.
I have the checklist I posted on my computer.

If you are hanging pieces try the attackers/defenders exercises at
http://www.chessgym.net/gen_howto.php
I always recommend that for achieving or improving the full board vision

Just play lots of games and review each one of them to learn from your blunders and avoid them in your future games.

GM Magnus Kingdom and IMBacon have posted beginner tip compilations which discuss premove checklist and a ton of other amazing stuff to improve beginner blunders. However IMRonilm1204 answers your question nicely.
I'm still a beginner myself, but for what it's worth I'd also recommend correspondence games until you have your premove checklist internalized and find your blunder count dropping. Also use the time to utilize the analysis board (engine off) to anticipate your opponents next move which will hopefully further improve your move choice and anticipate their plans/counter threats.
https://www.chess.com/clubs/forum/view/tips-from-me-highly-recommended-chess-tips-chess-tips-to-all-my-followers-2
https://www.chess.com/forum/view/for-beginners/imbacons-cheat-sheets
GM Magnus Kingdom blatantly copied IMBacon and said he made it up.
I have the checklist I posted on my computer.
The link to the list created by IMBacon is no longer valid? Is it posted in another thread?

It takes a LOT of practice to not blunder. As you get better, you'll look quaintly back at the blunders you did, and curse yourself for still blundering.
Honestly, a grandmaster can try to play against Stockfish, Houdini, or Komodo, and all those engines, and other less known engines, will go through him or her like a hot knife through butter.
But, there does come a point where you'll be able to keep track of the board, play into reasonable positions where your opponent would have to work to create a weakness in your position.
Work hard and the days of grabbing your opponent's piece without double checking to see if it's protected will be long gone. Presuming your playing at a reasonable time control.
Which in my opinion works out to the equivilent of 30 minutes for the first 60 moves, or even a longer time control.

I used to have a process, after I made a blunder.
I would go back, and try to remember exactly what I was thinking when I was made the move. And I don't mean analysis or lines.
Usually, I found the thought in my head was something like "Let's see what he is going to do about THIS!" Or "I am black, why am I grabbing the initiative??"
I started to notice these thoughts were subconscious red-flags, warning me I was about to do something stupid.
I've searched blundering and yes there is lots of great advice already up but what I want is like a checklist - do you guys who don't blunder run through a mental check before you press that tick confirm? So many times - just like literally a nano second after pressing I see my big fat blunder .... too late - bye bye queenie. Someone said in one of the posts - sit on your hands - something like that I think is the sort of advice I need. Many thanks.