Allow people to build homes on their own land, for the purpose of living in them, without applying for planning permission.
Why does this idea matter?
The restriction of the supply of residential land, imposed by means of the planning permission regime, is the main reason why plot prices are so ridiculously high. The idea of a plot of land, big enough for a family home, costing five times the average annual income, would be considered to be truly absurd in most of the world.
If a farmer wants to sell half an acre to someone who wants to build themselves a teepee and live in it, let them.
Encourage the amazing diversity, individual initiative and self-education that would flourish, were people allowed to design and build their own homes and live in them the way they want to.