From my perspective as a flying instructor I think that the following would help
1 - Redesign airspace where there are multiple and regular infringements (or at least wake up to the fact that there may be an issue with the design of the airspace). If it was an accident blackspot on a road we would take action to redesign not just keep moaning about it.
2 - Demand experience of busy airspace during navigation phase of PPL (for example transits of busy class d zones)
3 - Stop excluding private flyers from controlled airspace as this just means that they have less experience of flying in busy airspace. If we want them to get up to speed and act professionaly then we should treat them as qualified pilots who understand and know how to fly in the system (until proven otherwise).
4 - Adopt an easier IR for private pilots to get their knowledge and skill levels higher (i.e. get rid of the nonsense and provide them with practical knowledge and skills that they can then apply to fly safely).
It has been done and we all know where
Oh and here's one that might be more controversial....Send controllers to other countries for short secondments to see how others manage traffic (not related to infringements but might make controllers see that there is capacity for ppl flyers within those hallowed and fiercely protected zones)