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I love the fact you have given yourself tonnes of planning time, I really believe at least 70% should be spent planning and 30% doing. I think the answer to your question is also maybe too huge for anyone to know where to start. As an overall start, I would say look at the building materials you use, think about indoor air quality as a measure of the type of home you want, ventilation. We assume the materials builders spec are right but are they right for you and even for your builder to be using. I think the trades typically stick with what they know. Use non petrochemical paints like Graphenstone that reduce the CO2 in the air not cause more.
Have visual floor plans ready in each room as a tool for communication so there isnt any doubts in conversation about where things go and what gets put in. Make sure your building regs are done and your drain surveys and party walls done properly by a surveyor to really mitigate risk of where the costly things that will then hold up work could happen.
Hope that helps as a start and our of interest is there anything that feels different in this project to the one you did last.