Infrastructure — improve the roads (including better and more infrastructure for EVs), railways, metros and tramways. Major investment in connecting cities to each other by rail, and in urban public transport systems. Every big UK city should have a joined-up metro/tram/bus network like Amsterdam or Berlin.
Decouple public systems from politics, a bit like they did with the Bank of England: NHS, schools, criminal justice system + prisons, the BBC, the civil service.
Immigration — I want more of it. I would like to see politicians make more of the positive case for immigration and counter the prejudiced narrative that feeds misinformation, hatred and violence.
Housing. We need to build it, and not just huge estates of four- and five-bedroom homes just outside bypasses. Starter homes. Properly built and maintained social and council housing. Incentives for FTBs to buy derelict homes and renovate them. Estates of over a certain number of houses should be obliged to build/contribute financially to an increase in local services, including public transport, GPs and healthcare, emergency services, and schools.
Proportional representation.
Bonus points for abolishing the monarchy. £100million+ so a posh man can put on a hat? Ludicrous.