My dog constantly barks...what can i do to stop him..?

he's just over two now he's a cairn terrier and every little noise he barks at. i've tried everything like clicker training, distracting him, walking out the room, putting him in a crate to calm down but none of them work. i really don't want to give him up but he keeps barking at people, cars, birds and absoloutely everything and he dosent stop barking for like ten minutes.he barks whilst inside and out he's well fed and watered and is played with lots. please i need help