Surviving Your First Horde Night:
Hordes arrive from 22:00 - 06:00, every 7 days. Some horde nights can be hectic but occasionally they can be a little quiet. The import thing to remember about horde nights is that they will come for you from all angles, so don't concentrate on one side of your base with out checking the rest. I've had anything from 10 zombies to 50+, you want to make sure you've got a secure base with that amount! On one occasion there's been so many zombies that they've started to pile up on top of each other, almost to the point they could get over the wall that runs around the perimeter of the base. Most the time they will try and break down walls, doors, hatches etc The only way to combat this is to upgrade as much as you can and make it harder for them to bust through. The one zombie that can get around this is the spider zombie
This dude can climb walls no problem, which can be a major issue. The best way to stop this is to either kill them before they get to the top or build an overhang, he can only travel vertically so this stops him from getting over. (Video coming soon)
Spikes will be your best friend during horde nights, lay them everywhere around your base. Spikes will stop and slow zombies down but sometimes crawlers get through uninvited. I find it best to try and take the zombies done before they do too much damage to your spikes, otherwise you'll find you'll be replacing them a hell of a lot.
Just make sure you're counting your days till horde night and don't get left out in the open when it starts.
Leading up to horde night:
Make sure you're fully stocked on resources, spikes, arrows, anything you think you may need for a horde night. Craft your arrows and make your spikes before hand, so you're not having to mess about whilst they're attacking. Also make sure you're fully fed and hydrated.
Happy surviving!