At home:
1) Garlic, onions, shallots, chives and other stinkies have their own chopping board and may not ever be cut on any other board even if their dedicated board is in the dishwasher. Only stinkies may be cut on the stinkies cutting board. Nothing ruins a homemade passionfruit pavlova or strawberry shortcake quicker than getting that tang of garlic from flavour cross contamination.
2) There is a cheese tupperware in the fridge and all cheese goes in there to prevent the fridge and its other contents from smelling like cheese. Maytag Blue-scented mango moussecake and St. Albans-scented chocolate-coconut squares are gross.

On the road:
1) Drink water
2) Buy water as soon as possible when landed.
3) Drink water
4) Make sure there is enough drinking water the night before for the next day.
5) Drink water

Reminding myself to drink water constantly has helped prevent getting ill on the road. I have a Platypus water bottle tucked into each travel bag and one in my tote ready to be filled from a larger bottle I buy at a convenience store (or from the plane's refreshment trolley). You can never have too many Platys (though I dislike Vapur) I find that once I get dehydrated on the road, it's almost guaranteed that I will fall ill.