1. Make better decisions
Use decision making tools such as Plan/Do/Check/Act (PCDA - the Deming Cycle) or Six Thinking Hats to avoid policy blunders.
2. Be agile
Be ready to adapt policy to reality, or to fit changing circumstances. Small changes of detailed policy are not U turns, but fine tuning.
3. Remember all the value in life comes from integration
Be a one nation leader, remembering all four component parts of Britain. Think of education and employment as related, as are health and social care, and foreign policy and defence. Deterrence is more cost effective than warfighting but is a constant endeavour, preventative medicine will reduce acute health costs, and rehabilitation will reduce social care needs - train and employ more Physiotherapists and Occupational Therapists. Tailoring the education system to the likely future of employment will be infinitely better than going back to the old days.
4. Geography matters
The United Kingdom will always been part of Europe, but we can more accurately be described as a 'Euro-Atlantic' nation than a 'European' one. That gives us unique strengths and opportunities as well as threats and vulnerabilities. Threats may vary with political leaders coming and going, but vital interests do not.
5. To err is human...
From time to time mistakes will happen - whether policy or personal failings. Own up, take ownership, and the furore will soon go away.