One simple way to correct these types of blunders is after your opponent has moved, look first at every capture he has and ever check. Then before you make your move look at every capture and check your opponent has after your move. This will eliminate a lot of blunders.
I agree, I find myself playing much better when i take 20-30 seconds to analyze the board posistion
Don't sweat the small stuff and remember slowly but surely. That also works in life. I take breaks, long ones sometimes and sort out what has me busy in life. Then I come back with a fresh outlook on the game of chess. Then I play too many games and start the cycle all over. My Ratings on this website over the last few years demonstrates how if you are busy in life and you try to keep up with too many games, one of the two is going to suffer. For me, it's my chess play that suffers and everything in life is tidy and kept. I wouldn't want it the other way around. That's just crazy talk....