Bounce light is one of those things that takes a lot of practice to get down. the reason is because there are so many different sources from which the light can come from. Instead of having direct light shining into the person's face from the flash, the light might hit a bright white wall and get very diffuse, or light that might hit a bright red wall and turn a very warm color. For this reason, it is very difficult to make sure that bounce light will always look the same. And in turn, that is why it is very difficult to master bounce light.
I find that the best way to use bounce light when shooting headshots and wedding photographs is to 1st take note of the surroundings. You want to look at the wall and determine whether or not it's going to work for bounce light. If the wall is extremely dark or is not reflecting light very well, then you are not going to have a wall that can be used well for bounced light. If the wall doesn't work, check the ceiling. The only way that you're going to have a situation that will work, is if the wall or ceiling are white.