We all blunder. I do it quite a lot, especially in blitz and bullet. Though, in fast time controls, people usual blunder because they're rushing, and not thinking ahead. This is a common struggle that comes with the territory.
If you're blundering in slower games though, then those are certainly worth taking a look at.
Slap up a game that you want help understanding. Post specific questions about specific moves that you want advice on. Someone here will come along with advice to help you.
I been stuck between 600-800 for quite some time. With my rating swinging wildly up and down. Highest rating was 830. I need someone to look at my games and tell me what specific things I might be doing wrong?? Beyond just blundering there has to be something else??? I Analyze every other game these days. If you see some dumb move it's probably because I was trying something new and blundered. That or failing to implement a overly complex tactic I did not calculate well enough. I just need to know SPECIFC things I can study work and train. If you are a good coach I can offer compensation for this if needed. I'm not interested in 1 on 1 because I have done that many times. Yes, I quit some games. After screwing up I can become frustrated. (Just need someone to look at multiple games. Both my wins & losses.)
#1 I know I blunder. I try my best to improve this.
#2 I try to develop in the center.
#3 I only try to trade to gain a advantage
#4 I open up the center when I can after castling, more so when my opponent does not
#5 I try to exploit week squares and create a plan around it.
#6 I look for tactics and check mates. If I don't see them, I missed them.
#7 I simplify if possible.