Oh goodness my guy is 21 mths and still doesn't know where his feet are, VERY annoying. If he is walking by he steps on us...including the cat, she loves that. If we are laying down we get punched in the face with his paws.
He will probably grow out of his clumsy lanky body but in the meantime you could try teaching him some rear end awareness stuff to help him along. There are lots of suggestions and equipment on the net on how to do that. It cant fix clumsy but it will at least teach him where his body is in relation to the rest of the world he lives in.