How to become more responsible?

So, I'm 13 years old and I have a lot of exspensive things, but it seems like I'm always breaking them or loosing them and my mom keeps saying that i'm irresponsible and that I don't take care of anything. (e.g. I just bought a brand new Flip Video Camera and the screen cracked and target won't take it back; I have had 3 phones in the 2011 year and its only July; I got a nikon camera for Christmas but am no longer able to use it because I lost the charger; I've dropped my laptop a couple of times on the ground and it has some scratches; I left my ipod touch in my pocket when I washed my shorts) see what I mean, is there any tips or something that can help me become more responsible or even just appear more responsible to my mom?

This is funny. When You Have To Buy Them On Your Own! LOL…