Once you have the grip of the instrument under the chin sorted out, the next thing to address is the right hand’s grip on the bow. This can cause a great deal of trouble though in my opinion is not as tricky as the left hand. Again, the secret is to avoid tension; the hand must be relaxed. To do this, all four fingers and the thumb must be in contact with the stick, and all must be curved. This is hugely important. The most common grip errors are for the little or pinkie finger to lock and become straight and rigid. Do not allow this to happen. Another is for the pinkie to lift off the stick, which is also wrong. More subtle and harder to see but just as damaging is for the thumb to become stiff.
After a little while in the violin world, I know you will have seen this reaction: you have just gone into your friendly music shop and said, “My fiddle needs a new bridge. Can you sell me one?” You are shocked as the light outside dims, the interior of the shop becomes gloomy and the owner, in a voice that would render the bravest heart weak, intones, “You must never, ever, attempt to do any work on your violin yourself. Oh no. That is for the luthier to do. Now get ye hence and practise your scales.” And he refuses to sell you a bridge blank and you scuttle off with your tail between your legs thinking that everyone else in the shop must now consider you an uneducated oaf.