The blundering habit in blitz usually comes from your brain moving faster than your eyes. Most people think they need to slow down their moves, but the real trick is training yourself to do a quick visual scan - literally just sweeping across the board for pieces under attack - right before you commit. Two seconds sounds simple but it works, though heads up: if you're not actually *looking* at anything specific during those two seconds (just staring blankly), you'll slip back into autopilot. Make it active - check what your opponent's pieces can reach, especially near where you're about to move. That said, blitz isn't for everyone, and it's totally valid to stick with longer time controls if they feel better. Some people just aren't wired for that speed.