Try to don't do something else while you play?
Also avoid the fast games, becouse they reinforce bad tactics, and as sometimes you win you may think they are good moves and mess up your game. Fast games are for really good players. Maybe part of your problem is that the time presure is forcing you to play bad.
Hi Warchestra
If you are referring to your LIVE chess games, there is only one solution (in my mind, and I swear by this). I used to drop pieces left, right and center in almost every single game that I played. Then someone on the forums suggested that you should play SLOWER. Now I thought that slower meant to play 30-minute games. NOT SO. 
So I joined two turn-based tournaments where you have something like 2 days per move. At first I was still dropping pieces because I was playing turn-based in the same fashion as I was playing LIVE chess. 
But the thought of my opponents on the other side screaming with laughter every time I dropped a piece in a game where I had TWO DAYS to think about my actions just killed me. 
What I do now is to look at the position in a turn-based game. I decide on the move and make notes (in the notes section). Then I close the game. I move on to the next game, only to go back to my first one a couple of hours later. And miraculously I sometimes see "HEY! What on earth! You are hanging a piece AGAIN fool!". Use the analysis board as well. This will help you in "checking" your moves before you make them. After a while (because you are slowing down) you spot your mistakes long before your hand moves. 
And last but not least, I now spend at minimum 30 minutes a day on tactics. I use a mix of the Chess.com tactics trainer as well as books.
Obviously I still miss the odd tactic here and there (my rating is not quite where I want it to be), but my "hanging piecitis" problem has reduced a lot by following this approach and yours will too if you can force yourself to patiently wait for 2-3 days before your opponent makes a move.
And last but not least, if you do decide to follow this advice, don't make the mistake of joining 10 tournaments in the first go. I see players playing 50+ games at once, and I believe this will defeat the purpose, as you are rushing from one game to the next, instead of focusing on say 10 games and making "sound" moves.
Good luck!
I always get my eigenvalues wrong.
maybe because u suck
iam just kidding
Lmao. No you not
Concentrate on your game and look at every piece on the board. See what can happen if you put is there. Will it help me or will it just waist a turn. Personally the only stupid istakes that happen to me are when you have completely won a game and the you throw it away by moving your queen somewhere or not paying attention to where your opponent is and then just getting your queen killed and suddenlly your opponent just completly crushed you.
Also I get checkmated without even knowing it if I don't pay attention to the board.
I am OK at looking a couple turns into the future, but most games I just end up losing material stupidly, like moving a knight in front of a bishop and not getting anything from it. This usually happens when I am doing something else while I play, and I always realize it as soon as I drop the piece... Any help is appreciated.