Hey all!

I just got PhotoShop.so here i begin doing some nice background whit the brush,then i was thinking about pasting my character on the background,so i use the Magic Stick,so here come my problem,when i select something it go select a whole aera,and sometime it will select the thing you dont want to erase,so yea just need help whit that,like how deleting only around the character,sorry for bad english hope you will understand.
Oh and yea btw when you erase a part whit the magic stick it go white,then if i paste the image will the white still be there?