Looks like you have power... but that's about it.
You should get a double end bag and work on your speed and timing.
But since your just starting out you look pretty good.
-Staying on the balls of your feet. You're too flat footed.
-Start working combinations
-Move around the bag- don't stay in one place.
-Work on bobbing an weaving- you need to work defense and much as offense, bob and weave around the motion of the bag
-Get some resistance tubing and do some shadow boxing to work fast twitch muscles to develop your speed.
-Keep your hands up while your hitting the bag. Better to learn that in your basement, than during sparring or god forbid a street fight
-Do a lot of stretching
- Use more kicks