I wrote the longest and best answer ever haha. What happened?
Yeah see seems better but he needs to think against everyone. I think it is pretty basic stuff.
If he serve short sidespin or sidepsintopspin he needs to step out and be ready to attack, will proably get a flip or a bad short ball. Can have the racket pretty high since backspin is unlikely.
If he serve short backspin he need to be ready for a short ball, or a long push. Unlikely to get a flip. So be ready to step out and attack the ball if it comes long.
If he serve long backspin, he proably will get a topspin with a lot of spin. The same if he serve halflong. Lift the racket high and be ready to punch, flathit the ball or counterloop. This will prably be a good ball for that.
If he serve long side or topsping he proably will get a faster ball and need to lift upp the racket and be ready to just block.
He also needs to think about the placement. If he serve side to her forehand it most likely will come back to the backhand, if he serve reverse side to her backhand it most likeyly will come to his forehand.
He also needs to think the same when he is returning.
If he return short, he can get a short back, long push or flip. Hard to know, alot of options. Depends on opponent,
If he return long with backspin or half long he likely will get a topspin with alot of spin. Lift the racket high and be ready to punch, flathit the ball or counterloop. This will prably be a good ball for that. If he return long with nospin or topspin, the ball back will be fast and he nees to lift upp the racket and be ready to just block.
If he return fast the ball often comes back in the diagonal.
I also think it is important to have a own playingstyle, where you know how to serve, return and play to get the balls you are best at. example so you know when you do that kind of serve it is most likely to get it back there.
It is also important to look at the opponents, there are often patterns, they play the same way. The options above will be easier to anticipate when you try to look at the opponent and see how they play. Then you can have the advantage in the ball. Example you know that they always do a slow topspin if you push backspin to their backhand.
or In example i think she flips kind a much against you. If you know that she does that and steps out and be ready for it, you have the advantage! But since you know that she flips alot and if you want to stop it you can try to serve more short backspin so she flips in the net or more halflong so she can not flip.
She also seems like a forehandplayer, she wants to play forehand from forehand and backhand. Against them you want to play short and try to get to topspin first, and if you need to return long you want to return in the corners so they can not just work around and play forehand from the backhandcorner everytime. It also might be smart to lock her in backhand backhand.
If you play against a backhandplayer, you know you are not as good as them in backhand if you lose in backhand backhand, then you need to try to play more to their forehand and pocket. Especially to their pocket since backhandplayers want to play backhand in the middle and will have trouble knowing if they should work to play backhand or take their weaker forehand. If they bananaflip everything it might be a good idea to play short in their forehand and long to their backhand so they can not play the flip from the whole table.
This is proably oversimplyfied but it is still good to think a little like that.
I still think you should try to accelerate a lot more with your forearm so you get more spin on the ball. The ball will have better quality and will be safer.
Good Luck!