to the OP; i wish i can give you more in-depth tips but my TPB
has always been pretty sh!t from the get go is not my strongest skill (thats why i am CPEN now
)
but heres some general advice you should look out for.
1)
always try to push the ball right when the ball reaches the peak of its bounce; push the ball too late and its more likely to go to the net.
you can get away with an earlier timing sometimes but thats usually when you're trying to defend yourself from a fast topspin ball (and the only option you will have most of the time facing such balls).
2) i think this is a given but as with all table tennis techniques;
use your body to push the ball instead of just using your arm. you will be more consistent and have better control of the ball.
personally i way i approach TPB is how you would do a punch but more of a gentle jab instead of a full force Mike Tyson punch. i would turn my waist and hips to reel back my blade in position. once the ball comes, i turn my waist and hips outwards and use the momentum to push my forearm outwards to contact and "push" the ball. posture is low with knees bent throughout the technique.
elbow should be almost sticking to ur side and your blade should just go in a forward direction; not upwards or anything. if you're facing heavy topspin you press down on the ball.
also here's a tutorial on the rare technique of TPB smash but personally i dont think you really need it, its rare for a reason (low percentage shot);