Gosh he's a woolly fellow.
How long have you been riding? You say novice, so I'm assuming just starting out, apologies if I'm wrong.
I know everyone is saying how you should sit, leg position etc, and they are correct, but hey, you're just starting out, so just relax and enjoy yourself. You can work on correct position etc, when you start to feel at home in the saddle.
You have a nice straight back, and you've mastered getting your heals down.
Take deep breaths and try loosening your shoulders, then when you feel ready give a little more with the reins, this way when you've learnt to relax, you should find the rest of your body position falls into place.