Quick question...

Hey. I got a quick stupid question. I have PS8. And I always take images and use the eraser tool to kind of "cut" an image out to place onto another graphic. Like my icon. The girl I used the eraser tool on and then placed her on the icon. I was just wondering if there was a simpler way to do this at all. I mean I have been doing it this way for a long time but was just wondering if there were other methods. I know its a silly question, lol, sorry, but I would be of much thanks if anyone knew...