Raising a paw up
If you are with your dog and he is raising a paw up while focusing with her head down, i advise you to get out of his way. It means your dog is on the hunt and getting ready to pounce on some prey, usually a bird or other little animals.
Making himself look small.
Doing this by your dog basically means that he is just scared of something. However, if you meet a dog and see him doing this it means that he can be scared or the dog has been mistreated by his owner.