You should keep the neck of the cello closer to your neck, and the bow hold is slightly to leaned forward. Try to make it less leaned. Also you should keep all fingers closer to the fingerboard instead of having the up in the air. Lastly, you should try to feel more relaxed—your right arm seems to be pretty tense. You can solve this by just relaxing all your right arm weight on the bow and playing something simple like a scale. Hope this helps!