Never check spots you’re not allowed to go in. Don’t look often, because if you always try to find presents, your parents may become suspicious of you looking for them because you might move stuff around.
If it’s circular, it’s probably a CD or video game. If it’s short and wide, it’s probably a book or piece of clothing. If it’s large, it’s probably some sort of toy. If you can’t figure it out, open one side of the paper. Peek inside and tape it back together. Make sure it looks convincing. If it’s in a bag, just peek in and put the wrapping back quietly.