If you eat a healthy balanced diet you shouldn't need to carb load for a half. Make sure you are well hydrated before the run and take the water on offer if you need to. Don't try or take anything different on race day as this can upset your body and therefore your run. For a marathon i'd carb load 2 days before with slow release carbs. For me eating asap after a long run helps me recover so much quicker. Happy running
For half marathons, I'd say carb-loading isn't all that necessary, but if you are really pushing to get a PB, then eating pasta or a similar slow-releasing carb meal the night before is a good idea. Also, I have always found porridge + some berries on the morning of the race works wonders for energy.