1) Figure out the type of person who caused the trauma
2) Learn their psychology/world view (there are books on abusive personalities)
3) Learn to recognise them quickly
4) Have a plan to deal with them
5) Profit (you'll always have the upper hand)
By doing this you take away their ability to do anything. For some types this riles them up, which can be advantageous in eliminating the threat but also dangerous. You can plan for this.
Some suckers will throw money at that if you give it a colourful website with plenty of vague promises that you never have to deliver.