When I move attention part by part in the body I don't feel sensations in every part . Is this right ?
Initially you some times feel in some parts and not the other. Wait for a while to see if you feel something or not.
Or should I feel sensations in all body parts ?
Sometimes you might feel sensation on the whole body and some time not.
If you do not feel any sensations take those parts and look at them part by part, piecing and penetratingly, lingering until you see some sensation.
Sometimes I do quick sweep of attention from head to feet . I do this at any moment during the day when I remember to be aware of my body . Would this be helpful for practicing mindfulness of body ?
Yes. Try to do one down / up sweep in a in / out breath.
Or is there any better way of doing this ?
If you feel your whole body in one instance just keep looking at the body at some occasion without sweeping.