Thanks for taking the criticism constructively, and in the spirit it was intended.
I can offer a few pointers, but honestly there is an awful lot that needs to be worked on, so what I say is not comprehensive or particularly useful without correcting the whole thing.
But, to address your question:
You carry you right hand too low and too far forwards. It should be up against your cheekbone anytime you aren't smashing someone with it. You should not drop it or move it when you throw the left hand, currently you appear to do both.
You drop your left hand very often when you throw your right hand, and even when you don't it does not come far enough back to offer you proper protection.
When you go to throw a power punch with one hand, your other hand invariably goes flying in random directions. Always remember, the non-punching hand should be roughly against the cheekbone of the face on that side. Eg, if I throw my right hand, my left hand is back against the left side cheekbone on my face.
You don't set your feet at all when you punch. Because you're bouncing around like a mad thing, you get very little power or snap in your punches. You have to provide your punches with a solid base, so that you can screw your feet into the ground and generate power right the way through your body. As you get better, this will be the work of an instant, before you're back up on your toes again.
It is good that you are mobile, but move less and focus on moving effectively and with purpose. Every movement should put you a deliberate distance from the bag/opponent, that allows you to throw the shot or combination you want to use. It's no good bouncing into range and then deciding. Do that against a decent opponent and that split second of hesitation will get you eating some big shots.
Another problem you have is the height of your bag, as you seem to be either hunched up or punching down very often. This will be a bad habit that will invariably put you inside your opponents range before you are in a position to hit him with your own shots - never a good thing.
But again, all of the above will not be much use to you without a coach to drill you effectively, and partners to practice on.