When I was little, the following rule worked for me. Perhaps a little laborious but effective:
Before moving, look at all your pieces and those of the rival and see where each one points.
It may be simple, but the best way to avoid leaving pieces is to check the board before moving, instead of focusing on a specific area of the board. It is a children's trick, but it will surely help you not to leave pieces in your future games.
Thank you! For the most part, I'm good at doing this in slower time controls, but in blitz I get way too stressed and as a result I tunnel vision, even in slower blitz like 5+5. I guess a better question is this: how do I train myself to increase my speed of checking over the board? I don't hang pieces in classical or in 15+10, but anything faster and I begin to panic and miss something.
just started playing again a few months ago after not playing since middle school. I've been playing mainly classical over on another site and I've been improving a lot in that, just hitting 1850. however I make stupid blunders I would never normally make when I play blitz. I double check my moves in classical and rapid and I pretty much never hang pieces in those, but I hang something almost every game in blitz. how do I stop this? do I just keep practicing blitz so I can get used to double checking my moves faster? am I even able to fix the problem that way? how did you guys stop hanging pieces in blitz?