Make sure you have adequate fluids over the preceeding two to three days. I take a drink bottle to work and aim to get through a couple of refills each day.
With food, familiarity is key. Dinner the night before and race morning are not the times to try something new. Choose a balanced dinner the night before, carbohydrates are ideal - but make sure it's something you would normally eat. The same goes for breakfast - keep the food you choose and quantities consumed close to what you usually have. I often choose muesli or porridge, with a little milk or yoghurt.
If you usually drink water, stick to it for the race. Otherwise, try a training run with an electrolyte drink to make sure it agrees with you.
On race day there will be drinks every 3km, plus oranges at halfway. Plan your hydration. And if you aim at a time of about two hours you may need something more substantial than fluids alone. A muesli bar in the pocket, or half a banana, could be handy about the hour mark to keep energy levels up. But try this in training first.
Next week is the last week before race day, time for course familiarisation. I will share a few thoughts on the Whangarei Half Marathon course.