In order to do this you need to have laws that are designed to be reasonable for people to actually follow instead of laws that are designed to allow prosecutors to find a violation whenever they want to.
Actually enforcing them would create pressure to do that, but it would also create pressure to go back to selective enforcement when powerful people object to being subjected to the unreasonableness of existing laws.
A better solution might be to make a showing of selective enforcement a means to strike down a law. If you can show that someone else was doing the same thing without being charged then the prosecution either has to charge them too or that law is struck down and no one can be charged with it anymore.
Then instead of the incentive not to charge powerful people creating pressure for selective enforcement, the same incentive creates pressure to strike down the laws that can't reasonably be uniformly enforced.