You can improve it by doing footwork exercises. Just look it up on YT. 

Or jumping rope. It´s excellent to get rhythm.

#1 Learn how to do a proper serve. You won't impress teenage girls or others by looking into the camera after every two points but by knowing the rules of this game.

#2 Don't start with this monkey-style ready position. No matter if you play penhold, shakehand, pistol or naked with your chin - your blade is always above table height.

#3 Watch my playlists day and night, do shadow movements at home and ask your coach for multi-ball sessions. Although my playlists are primarily for J-Pen users, you'll also benefit from it. It's organized by various techniques, starting with the correct grip. There's a video of Kaii Yoshida you want to watch. Although you play somewhat of traditional because you've never learned a modern backhand (there's a reason you have a backhand rubber attached), you want to look-up videos for "penhold backhand" afterwards.

#4 This list can go forever but you need to learn the fundamentals first.

Well explained! 

Always start by learning the basic techniques, then focus on advanced stuff (footwork, heavy spin serves,...). 

I thought your serves were about right for your level, and certainly not where you need to start on getting better. The thing where you hang your hand to the floor while receiving looks a little weird and it's not very efficient, but I've seen some very strong juniors do the same thing (eventually their coaches train them out of it).

There's just a general lot of training that needs to be done.  Footwork or synchronizing your body with your stroke both sound good to me.

And I agree on the rude tone, really not necessary to just focus on negatives and tell someone they need to watch hours of professional players. 

 If you want to get even better, avoid using the reverse penhold backhand. If you try to master it now, you will become lazy and your footwork is going to suffer. 

+1, the elbow is way too far away from his body especially when pushing. He only won the game because the girl for some reason didn't attack his obvious sidetopspin serve. If he played in my club every single one of those serves will have been destroyed mercilessly. 

You look pretty comfortable with your equipment so get a penhold version if they make it or a blade with similar composition (use blade database). I'd echo what chicho said about not focusing on backhand too much and instead focusing on staple forehand footwork drills as otherwise your footwork could suffer but if I was you I'd still learn the RPB. My advice is to do drills with no more than one backhand in a row and focus on pivoting drills. You want to learn a very consistent backhand which keeps you in the rally but the forehand is what you will win points on 

Best of luck!