Disclaimer : I ain't reading 5 pages of replies, so what I'm about to tell you might have been said already
At first glance, a few things pop out :
- You're not twisting your fists at all when you hit, so you end up hitting with your thumb pointing upwards, or when you DO twist, it's not enough and you end up hitting with your small knuckles ( 4th and 5th ). Make sure you twist all the way, with your knuckles pointing up. You should be hitting with the 2nd and 3rd knuckles.
- You're not using your hips when you hit, so it's all arm punches. Try being on the ball of your toes and twisting your hips when you throw punches. For example, if you're throwing a straight right, your right foot should be on the ball of your toes.
- Right now, you're in a pattern of throwing a jab, waiting one second, throwing a straight, waiting one second, throwing a jab, waiting one second, etc. Mix it up, use hooks and uppercuts, throw 2 to 4 strikes at a time. Jab, straight, left body hook - wait - hook, hook, left uppercut, straight right - wait - etc.
- You're only throwing head strikes. Mix it up.
Keep it up.