I have some resources at the bottom of this blog post:
https://www.chess.com/blog/KeSetoKaiba/opening-principles-again
Everyone blunders; even grandmasters. We are human and don't play consistently well all the time; what makes them professionals at chess is that they blunder much less frequently, but they still blunder. Have patience and understanding towards yourself when you do occasionally blunder. Try to analyze your own games to learn from your mistakes and hopefully you'll blunder less often.
I am so curious about how do I raise my rating. I know many useful openings, how do fork, how do pin, how do play correct opening, middle game, and Endgame, but somehow I always play blunder or bad move in 50% to 60% of games I played. My goal is reach to 1000, but I'm not sure I can improve myself. Can anyone tell me some tips?