This is looking great already! The overall timing is perfect
The way I would add more power is to make sure that your build up happens in the opposing direction to the ultimate motion. So ideally you want the figure to squish downward before springing up. And then you want to have a longer buildup of energy, keep squishing a little more every frame, really ease into the final pose, and then hold that final pose for just a moment before releasing.
And I would take another look at the feet, having them spring in and out makes it appear to release it's energy early before the big motion. Have everything moving in one direction for the whole duration of the buildup.
As for the effects you really can't overdo it. Use lots of frames, lots of little tendrils and flecks of light that slowly fade away. Especially for the launch. Rather than having the effect move upwards like it does try having it dissipate in place (i.e. make it thinner and break apart a little frame by frame until it is gone)
Overall I would say the biggest thing you want in your timing is contrast, you want the buildup and the fade out to linger as long as you can and have the motion happen in just one frame like you have now.
Good luck
