How to teach puppy to stop barking at people?

My 5 month old Border Collie/ Australian Shepherd mix puppy barks at people and other dogs. She will not bark at a person unless they are approaching us. She doesn't care if they are across the street or far away, but if she sees them walking towards us, she goes crazy. She also barks at other dogs like crazy. I dunno why she's doing this, she has been socialized a lot. Grew up with tons of people, cats, dogs. She is exercised as much as a 5 month old puppy needs. Should I try a squirt bottle or pennies in a bottle? Tips would be great, thanks.