Getting a foothold in a strong, fortified shelter is the deference between living a life of mild zombie difficulty or living on the road, running from place to place, or even being eating by your friends and neighbors. Making sure zombies can’t get into your home is pretty obvious, but keeping them off your entire property with fences, moats, etc is key. An open property gives you piece of mind, a place to grow a garden and work on projects, or just to get a nice tan.
Blocking off zombies is very important, but make sure you leave yourself a way out. You may want to go out and scavenge for food/parts or maybe your fort has been compromised and you need to make a quick exit.
When looking for a shelter, being prepared before the outbreak can be very useful. Stores make a great find, especially sporting good stores. Dehydrated food, guns and ammo in abundance is a dream come true in a post-apocalyptic world. Before the outbreak happens, scout out great places to commandeer & make sure it will have a great end game.
If you don’t want the undead beating at your door, make sure you keep the noise level to a minimum, also any lights, fires and cooking smells may bring the hoard to your doorstep.
Remember: Guns make noise, so if a single zombie wanders on to your lot, take it out silently. An axe to the head may be a bit more risky that a shotgun to the face, but it wont bring all his buddies running.